Periodic Properties and Variations of Properties ICSE Class 10 Chemistry Important Questions

Study Material

Students of ICSE Class 10 should refer to Periodic Properties and Variations ICSE Class 10 Chemistry Questions below which have come in past board exams. You should always go through questions that have come in previous years. This will help you to understand the pattern of questions in ICSE Class 10 Chemistry and prepare accordingly. This will help you to get better marks in ICSE Class 10 Board Exams.

ICSE Class 10 Chemistry Important Questions Periodic Properties and Variations of Properties

Periodic Properties and Variations of Properties is an important chapter in ICSE Class 10 Chemistry. Our faculty has prepared the following ICSE Class 10 Chemistry Questions and answers based on the latest syllabus and books issued for the current academic year. Please refer to the solved questions below and also see links provided for other chapters.

Periodic Properties and Variations of Properties ICSE Class 10 Chemistry Questions

I. DO WE KNOW ?

The HISTORY of Periodic table
Early chemists – Arranged elements on basis of – valency, metallic and nonmetallic character.

Dobereiner’s Law of Triads :Dobereiner [1815] arranged the elements in groups of three according to their atomic weights and said that when chemically similar elements were arranged in increasing order of their atomic weights then the weight of the middle element was approximately the arithmetic mean of the other two in the triad.

The law was discarded : It did not hold true for all elements.

Newland’s law of Octaves : He arranged the elements in groups of eight according to their atomic weights. He said that when elements were arranged in the increasing order of their atomic weights, such that the eighth element showed a repetition in properties of the first element.

The law was discarded : The law did not leave any spaces for undiscovered elements.

Mendeleeff’s Periodic table : He arranged elements according to increasing order of atomic weights in the form of a table. He stated that physical and chemical properties of elements are periodic functions of their atomic weights.

Merits of Periodic table : The table was advantageous as it could predict properties of certain undiscovered elements, corrected atomic weights of certain elements.

The law was discarded : It could not find position of isotopes, rare earth elements and chemically similar elements did not fall in the same group and elements with dissimilar properties were grouped together.

Periodic Properties and Variations of Properties ICSE Class 10 Chemistry Questions: A. Introduction (Modern Periodic table)

1. a) State Modern periodic law.
Ans. The physical and chemical properties of elements are periodic functions of their atomic numbers.

b) How does modern periodic table differ from Mendeleeff’s periodic table.
Ans.

Periodic Properties and Variations ICSE Class 10 Chemistry Questions

2. Why is atomic number considered as the fundamental property of an element?
Ans. Atomic number is equal to the number of electrons in the energy shells of an atom & hence determines the chemical properties of elements. Hence atomic number is fundamental property of an element.

3. State the salient features of the modern periodic table.
Ans. 1. The modern periodic table is based on atomic number of elements.
2. The modern periodic table is divided into :
(a) Groups (Vertical columns)
(b) Periods (Horizontal rows)
3. There are 18 groups.
4. Members in the same group have the same outermost electronic configuration and therefore they have the same valency.
5. Groups are further given special names :
Groups IA to VIIA – normal elements.
Groups IA – alkali metals.
Group IIA – alkaline earth metals.
Groups IB to VII B and VIII – transition metals.
Zero group – Noble gases. Group 1 (IA) – 2 (IIA) : Reactive metals.
6. The number of electrons in the valence shell of normal elements is determined by its group number.
7. The metals are placed to the left, the non metals to the right and the transition in the centre of the table and inner transition at the bottom of the table.
8. There are 7 periods in the table.
9. Elements in the same period have the same number of shells. The period number determines the number of shells.
10. The number of electrons in each period increases from left to right in the same electronic shell.
11. Periodicity in properties i.e. the recurrence in properties are seen with elements belonging to the same subgroup in the periodic table after a difference of 2, 8, 18 or 32 in atomic numbers due to recurrence of similar valence shell electronic configuration.

Periodic Properties and Variations of Properties ICSE Class 10 Chemistry Questions:

B. Periods

1. Each period begins with an element with one electron in its outermost shell and ends with a noble gas with a stable (complete) electronic configuration.
2. Position of hydrogen is uncertain and it can be placed in group IA as well as Group VIIA.
3. The inner transition elements called Lanthanides and Actinides which belong to the 6th and 7th period are not accommodated in the main body of the periodic table but are placed separately at the bottom of the table.
4. Period number signifies the number of electron shells of an element.
Ex. : Period – 1 : Elements have 1 electron shell
        Period – 2 : Elements have 2 electron shell
5. Across the period : Similar : Number of electron shell
                                Change : Number of valence electrons.
The horizontal rows called periods are numbered from 1 to 7 and are as follows :

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

Bridge Elements in Period 2
Bridge Elements show similarities in properties diagonally with the period of the next group.

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

GROUPS

1. Groups are vertical columns, 18 columns present, sub – divided into A and B group.
2. Metals are placed in group IA (alkali metals) and IIA (alkaline earth metals) Metalloids are present in group IIIA, IVA, VA, VIA and non – metals placed in groups IVA, VA, VIA, VIIA, Inert gases in Group 18 or group zero.
3. Elements in the same group have the same valency e.g. sodium and potassium both lie in group IA and both have 1 electron in their outermost shell.
4. The two groups of elements : The inner transition elements called Lanthanides and Actinides which belong to the 6th and 7th period are not accommodated in the main body of the periodic table but are placed separately at the bottom of the table.
5. Group number signifies number of valence electrons of an element
Ex.: Group IA  : Elements have 1 valence electron
       Group IIA : Elements have 2 valence electrons
6. Along the group : Similar : Number of valence electrons
                              Change : Number of electron shells.

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

4. Give the relation between atomic number and atomic mass number.
Ans. As atomic number increases, atomic mass number increases as well. Atomic number (Z) is the number of protons in the nucleus of an atom.
Mass number (A) is the total number of neutrons and protons present in the nucleus of an atom.
        A  =                Z      +                   N
Mass number      Atomic number       Number of Neutron
Usually the mass number is double of the atomic number. So the neutron to proton ratio remains close to one.
Elements having n/p ratio close to unity are light elements.
Higher the n/p ratio, more unstable is the element. Elements having n/p ratio higher than 1.5  are radioactive elements.  That is why metals like uranium and polonium are unstable and radioactive. 

5. Distinguish between Alkali metals and Halogens or Group IA and Group VIIA elements.
Ans.

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

6. What is periodicity in properties?
Ans. The recurrence of similar properties of the elements when they are arranged
in increasing order of their atomic number, after certain regular intervals, is called periodicity in properties of elements.

7. What are the causes of the periodicity of elements?
Ans. Periodicity in properties of elements are seen because in the modern periodic table, the elements are arranged according to their atomic numbers and its arrangement of electrons.
The physical and chemical properties of elements largely depends upon the number and arrangement of electrons in various shell including valence shell. Hence Periodicity in properties of elements are seen due to same outermost electronic configuration occuring periodically.

8. Show the Periodic trends?
Ans. Periodic trends in properties include:
1. Atomic size
2. Ionisation Potential
3. Electron affinity
4. Electronegativity
5. Metallic and non metallic character
6. Other Physical and chemical properties (Density, Melting and Boiling point)

9. Define the following :
(a) Atomic size
Ans. The distance from the centre of the nucleus to the outermost shell of an atom is called the atomic radius of that atom.

(b) Ionisation potential
Ans. Ionisation potential is the amount of energy required to remove a loosely bound electron from the outermost shell of an isolated gaseous atom.

(c) Electron affinity
Ans. Electron affinity is the amount of energy released when an electron is added to an isolated gaseous atom to form an anion.

(d) Electronegativity
Ans. Electronegativity is the tendency of an atom to attract electrons towards itself in a compound / molecule.

(e) Metallic character
Ans. The tendency of an element to lose electrons and form cations is called electropositive or metallic character.

(f) Non- Metallic character
Ans. The tendency of an element to accept electrons to form an anion is called its non-metallic or electronegative character.

10. What are the factors affecting the following properties?
(a) Atomic size

Ans. (i) Number of shells that are present – As the number of shells increases, the atomic size also increases.
(ii) The nuclear charge – As the positive charges increases, the attraction to the outermost shell increases, hence pulling it inwards and decreases the size.

(b) Ionisation potential
Ans. (i) The atomic size – As atomic size increases, the nuclear attraction on the outermost electron decreases and hence the electron can be removed easily. Thus, the I.P. decreases.
(ii) The nuclear charge – As the number of protons (positive charge) increases the attraction to the outermost electron also increases and thus the amount of energy required will be more as the electrons will be firmly held.
(c) Electroaffinity
Ans. (i) Atomic size : The smaller the atomic size, the effective force of attraction between the nucleus and the valence electron is greater and hence electrons are held more firmly.
(ii) Nuclear charge – Increase in nuclear charge, increases the effective attractive force on the valence electrons, hence electron affinity increases.

(d) Electronegativity
Ans. (i) Atomic size : The greater the atomic size, the electrons are farther away from the nucleus, hence experiences a lesser force of attraction.
(ii) Nuclear charge – Increase in nuclear charge causes electron attraction with a greater force, thereby increasing the tendency of an atom to attract electron towards itself.

(e) Metallic and Non-Metallic character
Ans. (i) Atomic size : The greater the atomic size, more is the ease by which an electron can be lost by an atom, hence more is the metallic character. Whereas, greater atomic size results in less force of attraction thereby reducing the non – metallic character.
(ii) Nuclear charge – The greater the nuclear charge, greater is the force exerted by the nucleus on valence electrons, thereby making it difficult to remove electrons and easier to gain electrons. Hence, metallic character decreases and non – metallic character increases.

11. Give the trends in periodic properties
(i) Down a group (ii) Across the period
(a) Atomic size
Ans. (i) Down a group : The number of shells increases. So although the nuclear charge increases, the attraction to the outermost electron decreases. So down a group, the atomic size increases.
(ii) Across the period : The number of shells remains the same. So as the nuclear charge increases due to increase in atomic number, the attraction to the outermost electron increases and pulls the outermost electron inwards.
Therefore across a period, atomic size decreases.
Neon is an inert gas which has larger radius.

(b) Ionisation potential
Ans. (i) Down a group : The atomic size increases. So although the nuclear charge increases, the attraction to the outermost electron decreases and thus the amount of energy required to remove the outermost electron will be less.
So down a group, the ionisation potential decreases.
(ii) Across the period : The atomic size decreases and the nuclear charge increases due to increase in atomic number, the attraction to the outermost electrons increases and pulls the outermost electrons inwards. And hence the amount of energy required to remove the electron will be more as the electrons will be firmly held.
Therefore across a period, ionisation potential increases.

(c) Electroaffinity
Ans. (i) Down a group : The atomic size increases. So although the nuclear charge increases, the attraction to the outermost electron decreases. So down a group, the Electron affinity decreases.
(ii) Across the period : The atomic size decreases and the nuclear charge increases. Hence, the attraction to the outermost shell increases and the tendency to gain electron also increases to form an anion. Therefore across a period, Electronic affinity increases.

(d) Electronegativity
Ans. (i) Down a group : The atomic size increases and the electron affinity decreases.
Thus down a group the electronegativity decreases.
(ii) Across the period : As the nuclear charge increases and atomic size decreases, the electron affinity increases from left to right . Therefore, across a period the electronegativity increases.

(e) Metallic and Non- Metallic character
Ans. (i) Down a group : As we go down a group, the atomic size increases, therefore the nuclear attraction on the outermost electron decreases. Thus, the atoms placed down the group will lose electrons easily as compared to the elements placed on the top in the same group.
Thus down a group, metallic character increases and non metallic character decreases.
(ii) Across the period : As we move from left to right in the period, the atomic size decreases and nuclear charge increases. Consequently, the attraction on the valence electrons increases and therefore ionization potential increases.
Thus as we move across a period, the metallic character decreases and non-metallic character increases.

12. Arrange the elements of Group 17 according to the given conditions.
(a) increasing order of atomic size,
(b) increasing non-metallic character,
(c) increasing electron affinity,
(d) decreasing electronegativity.
Ans. a) F < Cl < Br < I < At
        b) At < I < Br < Cl < F
        c) At < I < Br < F < Cl
        d) F > Cl > Br > I > At

13. Answer the following :
(a) Which two elements in period 2 would show chemical properties similar to magnesium? What is the basis of your choice?
Ans. Lithium and Beryllium. Lithium has similar chemical properties, since lithium and magnesium are bridge elements and hence they have diagonal relationship. Beryllium and magnesium are present in the same group, have same number of valence electrons and hence have similar chemical properties.

(b) Which of the following is greater in size? Why?
(i) An atom or cation (Na or Na+)
Ans. An atom (Na). Because an atom has one shell more than its corresponding ion, also due to loss of electrons number of protons are more than the number of electrons in a cation. This causes increased force of attraction thereby reducing its size.

(ii) An atom or anion (Cl OR Cl–)
Ans. An anion (Cl–). Because an anion has complete outermost shell this results in force of repulsion among the electrons, thus increasing the atomic size.

(iii) Fe2+ or Fe3+
Ans. Fe2+. Because Fe2+ is formed by loss of 2 electrons, whereas, Fe3+ is formed by loss of 3 elctrons, hence the electrons are attracted by less force in Fe2+ compared to Fe3+. Thus, size of Fe2+ is more than Fe3+.

(c) What do you understand by successive ionization energies?
Ans. The energy required to remove the residual electrons, one by one, is called successive ionization energy.

(d) (i) What are alkali metals?
(ii) Why alkali metals do not occur freely in nature?
Ans. (i) Alkali metals are metals present in IA /1st group of the modern periodic table whose oxides form strong alkali.
(ii) Alkali metals have strong metallic character and can be ionized readily to form compounds. Hence, they do not occur freely in nature.

(e) Why does the metallic character decreases from left to right across the period, in the periodic table?
Ans. The elements to the left of the periodic table have a tendency of losing electrons easily as compared to those to the right. As we move from left to right of the period, the electrons of the outer shell experience greater nuclear attraction because of increasing nuclear charge.
Thus, electrons of the elements to the right of the table do not lose electrons easily, so are non – metallic in nature. Thus, the metallic character decreases from left to right across the period, in the periodic table.

(f) Why does metallic character increases down the group?
Ans. As we move down the group the number of shells increases. This causes the effective nuclear force to decrease due to the outer shells being further away; as atomic size increases. The electrons of the outermost shell experience less nuclear attraction and so can lose electrons easily thus showing increased metallic character.

14. Give reasons for the following :
(a) Atomic number of an atom is more important than its relative atomic mass.
Ans. Because chemical properties of e lements depend on the electronic configuration which is equal to the number of electrons or protons (atomic number). The elements which have similar electronic configuration are put in the same group as they show similarity in their properties. On the other hand, Atomic mass number does not give information about the electronic configurations or electrons in the atom.

(b) Group 17 elements are strong non metals and group 1 elements are strong metals.
Ans. Due to high electron affinities, Group 17 elements tend to accept electrons and form anions. (They have 7 electrons in outermost orbit) and hence are strong non – metals.
Due to low ionisation potential to acquire a stable state, elements in Group 1 tend to lose electrons easily to form cations & hence are metallic.

(c) Atomic size of Group 18 elements is more than elements of 17.
Ans. In elements of Group 18 the outermost shell is completely filled and this results in a force of repulsion among the electrons, thus increases the atomic radius and the atomic size thus increases.

(d) Electron affinity of noble gases is zero.
Ans. Noble Gases already have a stable outer electronic configuration and hence find it difficult to accept electrons hence no energy released by the atom to form an anion, thus the electron affinity of Noble Gases is 0.

(e) Sulphur is placed is Group VIA, chlorine in VIIA, but Argon in Group 0.
Ans. The group no. signifies the number of valence electrons of an elements Sulphur (2, 8, 6) has 6 electrons in the outermost electronic shell so it is placed in Group VIA.
Chlorine (2, 8, 7) has 7 electrons in valence shell, so it is placed in Group VIIA.
Argon (2, 8, 8) has 8 electrons which is a stable electronic configuration. It is therefore an inert unreactive element with valency 0. Hence placed in Group 0 (Also known as Group 18).

(f) In the same period and subgroup a gradual change in a particular property may be seen.
Ans. The property of an element is the periodic function of their atomic number.
Across the same period or subgroup the electronic configuration of the elements show gradual change. Hence a gradual change in particular property may be seen.

(g) Phosphorous, sulphur and chlorine are electronegative element of the periodic table.
Ans. Phosphorous, sulphur and chlorine are placed at the right side of the periodic table, where the Ionisation potential of the elements increases and also electron affinity increases. Thus these elements attract electron towards them and hence are electronegative elements of the periodic table.

(h) Fluorine is the most electronegative element of the periodic table.
Ans. The electronegativity increases across the period upto halogens/VIIA group and also decreases down the group. As fluorine is the first element in VIIA group/halogens, the electronegativity of fluorine is maximum. Hence fluorine is the most electronegative element.

(i) Atoms with large atomic radii and low ionisation potential are more metallic in nature.
Ans. Atoms with large atomic radii and low ionisation potential can easily lose electrons forming cations. Thus atoms with large atomic radii show more metallic nature.

(j) A decrease in ionisation potential of an element leads to increase in metallic character of that element.
Ans. A decrease in ionisation potential of an element leads to increase in ease of removal of electrons, therefore increasing the metallic character.

(k) The reducing power of element increases down the group while decreases across a period.
Ans. Reducing power depends upon the ease with which an element can lose electrons. On moving down the group the atomic size increases and therefore it becomes easier for the elements at the bottom of the group to lose electrons. Hence, the reducing power increases down in a group.

(l) Elements in the same group have similar chemical properties.
Ans. Elements in the same group have same number of valence electrons and hence have similar chemical properties.

ADDITIONAL QUESTIONS

A. Name the following with reference to periodic table :

1. The valency of elements of group 2.

Answer

+2

2. The alkali metal in period 3.

Answer

Sodium

3. The liquid halogen.

Answer

Bromine

4. The metalloid in period 2.

Answer

Boron

5. The inert gas having configuration 2,8.

Answer

Neon

6. The element with largest atomic size in period 2.

Answer

Lithium

7. The element with highest ionisation potential from the elements of period 3.

Answer

Argon

8. The strongest oxidising agent in period 3.

Answer

Chlorine

9. The formula of the oxide of element in period 3 group IA.

Answer

Na2O (Sodium oxide)

10. The element with highest electronegativity from the elements S, Cl, P, Si.

Answer

Chlorine

11. 2 elements which are in the same group as carbon.

Answer

Silicon and Germanium

12. Alkali metal in period 2.

Answer

Lithium

13. Alkaline earth metal in period 3.

Answer

Magnesium

14. Two metals in period 2.

Answer

Lithium, Beryllium

15. Two metals in period 3.

Answer

Sodium, Magnesium or Aluminium

16. Number of shells in 3rd period.

Answer

3

17. Most electronegative element in period 3.

Answer

Chlorine

18. A non metal with valency 3.

Answer

Nitrogen

19. An element in the same group present with sodium.

Answer

Caesium/Francium/Rubidium/Potassium/ Lithium

20. Element with maximum non metallic character from period 2.

Answer

Fluorine

21. The element with the largest Atomic size from the elements of period 3.

Answer

Na

22. Group with valency 0.

Answer

18 Group, Zero Group (Noble Gas)

23. Noble gas with duplet arrangement of electrons.

Answer

Helium

24. The first 3 Alkali metals.

Answer

Lithium, Sodium, Potassium

25. Smallest Atom in period 3.

Answer

Chlorine

26. Groups in which transition metals are placed. 

Answer

B Group or 3 – 12 Groups

27. The elements from Li, Na & K having least number of electron shells.

Answer

Lithium

28. The element from C, O, N, F having maximum nuclear charge.

Answer

Fluorine

29. The group and period to which an element ‘Y’ with electronic configuration 2, 8, 8, 1 belongs to.

Answer

Group 1, Period 4

30. The element having lower ionization potential out of Be and Mg.

Answer

Magnesium

31. Name the periodic property which relates to the character of element which loses one or more electrons when supplied with ene

rgy.

Answer

Metallic character

B. Multiple Choice Questions :

1. With reference to the variation of properties in the Periodic Table which of the following is generally true?
a) Atomic size decreases from left to right in a Period.
b) Atomic size increases from left to right in a Period.
c) Atomic size decreases from top to bottom in a Group.
d) Ionization potential increases on moving from top to down.

Answer

a) Atomic size decreases from left to right in a Period.

2. With reference to the variation of properties in the Periodic Table which of the following is generally true?
a) Electron affinity decreases from left to right across a Period.
b) Electron affinity increses from left to right across a Period.
c) Electronegativity decreases from left to right across a Period.
d) Electronegativity increases going down a Group.

Answer

b) Electron affinity increses from left to right across a Period.

3. Which of the following statement is true?
a) Halogens are bad conductors of heat and electricity.
b) Atomic size of halogens decreases on moving down the Group.
c) Electronegativity of halogens increases on moving down the Group.
d) Electron affinity increases on moving down a Group.

Answer

a) Halogens are bad conductors of heat and electricity.

4. Which of the following statements is true?
a) Number of electron shells decreases progressively by one down a Group.
b) Elements in the same Group have the different number of electrons in their outermost shells.
c) Elements in a Period have the same number of electron shells.
d) Elements in a Period have different number of electron shells.

Answer

c) Elements in a Period have the same number of electron shells.

5. Which of the following statements is True?
a) There are 7 Periods in the Modern Periodic Table.
b) There are 18 Periods in the Modern Periodic Table.
c) There are 7 Groups in the Modern Periodic Table.
d) There are 8 groups in the Modern Periodic Table.

Answer

a) There are 7 Periods in the Modern Periodic Table.

6. The chemical properties of an element depends on its:
a) atomic mass
b) atomic number
c) atomic energy
d) atomic volume.

Answer

b) atomic number

7. Which of the elements Li,Na,Mg and Al has the lowest ionization potential?
a) Li b) Na
c) Mg d) Al

Answer

b) Na

8. The atomic number of an element X is 20. It lies in the Group:
a) l b) 3
c) 2 d) 7

Answer

c) 2

9. On moving down a Group, the number of valence electrons:
a) remains the same
b) increases
c) decreases
d) increases progressevely by 2

Answer

a) remains the same

10. An element in period 3 whose electron affinity is zero
a) Sulphur
b) Sodium
c) Neon
d) Argon

Answer

d) Argon

11. An alkaline earth metal
a) Lead
b) Potassium
c) Calcium
d) Copper

Answer

c) Calcium

12. An element with highest ionisation potential
a) Caesium
b) Fluorine
c) Helium
d) Neon

Answer

a) Caesium

C. Choose the correct alternative : 

1. Elements of group VII A are strong oxidising (oxidising / reducing) agents since they are electron acceptors (acceptors / donors).

2. An atom is said to be a metal if it loses (gains /loses) one or more electron

3. Down a group the density of elements increases (increases / decreases).

4. Ionisation potential of elements across the period increases (increases /decreases).

5. Electron affinity is the amount of energy released (absorbed /released) when an atom in the gaseous state accepts  (accepts / donates) an electron to form an anio

6. Elements with high electronegativity are usually non-metallic (metallic / non-metallic).

7. Neon in period 2 is likely to have larger (larger / smaller) atomic size than flourine and its electron affinity value would be zero (greater / less / zero) compared to flourine.

8He has the highest ionisation potential among the elements of period 1,2, (He, Ne, Ar)

9. Down a group, electron affinity decreases (increases / decreases).

10. The positive charge on the nucleus of an atom equivalent to the atomic number of the element is called nuclear charge (atomic charge/ nuclear charge).

D. Fill in the blanks

1. Horizontal rows in the periodic table are called ________

Answer

Periods

2. Moving across a period from left to right the atomic size of atoms ________

Answer

decreases

3. Across a period, the valence electrons ________.

Answer

increases

4. The properties of elements are periodic function of their ________

Answer

atomic number

5. Moving across a ________ the elements show an increase in non-metallic character.

Answer

period

6. Similarities in the properties of elements in a Group are that they have the same ________.

Answer

valence electrons / valency

7. Elements at the bottom of the group would show ________ metallic character than the element at the top.

Answer

more / greater

8. The element in Group 17 which is liquid at room temperature is ________.

Answer

Bromine

9. There are ________ periods in the periodic table.

Answer

7

10. Across a period the electropositive character ________ and down a group the electronegative character ________.

Answer

decreases, decreases

11. The Atomic size of Neon is ________ than that of Fluorine.

Answer

more

12. Nuclear charge of an atom is the charge present on the nucleus of an atom equivalent to the atomic ________.

Answer

number

13. An element ‘Q’ in period 3 has high electron affinity and electronegativity. Thus it is likely to be a ________.

Answer

non – metal

14. Element B is to the right of element A. Element B is likely to be ________ non-metallic in character than element A.

Answer

more

15. Increase in nuclear charge of an atom ________ its tendency of an atom to lose electrons.

Answer

decreases

E. Answer the following question

1. State the number of elements in period 1, 2 and 3. Give 2 examples of each.

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

2. With reference to the first 3 periods, answer the following.

(a) Formula of sulphate of element with Z = 13.
AnsAl2(SO4)3.

(b) Element with highest Ionisation potential.
AnsHelium.

(c) Common feature amongst elements of group VIIA.
Ans7 electrons in outermost orbit or they have valency 1.

(d) Number of electrons in outermost shell of element with atomic number 16.
Ans6.

(e) Write the electronic configuration of element in the third period which gains one electron to form anion?
Ans2, 8, 7.

(f) Bonding present between oxide of element with atomic number 11.
Ans. Electrovalent.

3. Keeping the least reactive element first rearrange the following element
(i) 
Cl, Br, I.
Ans. I, Br, Cl.

(ii) Na, K, Li.
Ans. Li, Na, K.

(iii) Na, Mg, Al.
Ans. Al, Mg, Na.

4. An element X belongs to period 3 and group Find :
(i) 
Number of valence electrons.
Ans1.

(ii) Is it a metal or non metal?
Ans. Metal.

5. An element Z is in the second period and Group VI A of the periodic table.
(a) 
Is it metal or non metal?
Ans. Non – metal.

(b) Number of valence electrons?
Ans6.

(c) Valency of element?
Ans2.

(d) Electronic configuration of element
Ans2, 6.

(e) Formula of the compound with sodium.
Ans. Na2Z.

(f) Name of the element?
Ans. Oxygen.

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

(i) Which element belongs to Group Zero?
Ans. Z.

(ii) Which element belongs to Group VA?
Ans. Y.

(iii) Which element is placed in Group IIIA?
Ans. X.

(iv) Which period do these elements belongs to?
Ans. 2nd period.

7. (a) Write the oxide of element with Atomic number 13.
Ans. Al2O3.

(b) Bonding present in oxide of an element with atomic number 1.
Ans. Covalent (Polar).

(c) The element with highest ionisation potential amongst halogens.
Ans. Fluorine.

(d) Number of electrons present in valence shell of elements placed in Group VA.
Ans. 5.

(e) Name a metalloid in period 3.
Ans. Silicon.

8. A group of elements in the Periodic Table is given below:
Beryllium
Magnesium
Calcium
Strontium
Barium
Radium

Answer the following questions in relation to the above group of elements:
a) Which element has the most metallic character?
b) Which element would be expected to have the highest electronegativity?
c) If the electronic configuration of beryllium is 2, How many electrons are there in the outermost shell of calcium?
d) The atomic number of calcium is Write the chemical formula of the compound formed when calcium reacts with chlorine.
e) State the metallic nature of the elements of group to the left of this group in the Periodic Table. Justify your answer.

Ans. a) Radium b) Beryllium c) 2 electrons d) CaCl2
e) More metallic because metallic character increases from right to left.

9. A group of elements in the Periodic Table is given below:
Fluorine
Chlorine
Bromine
Iodine

Answer the following questions in relation to this group of elements:
a) Which element has the most non-metallic character?
b) Which element would be expected to have the highest ionization potential?
c) If the electronic configuration of fluorine is 2, How many electrons are there in the outer shell of iodine?
d) The atomic number of fluorine is Write the chemical formula of the compound formed when fluorine reacts with magnesium.
e) Will the elements in the group to the left of this group in the periodic table be more or less non-metallic in character?
Ans. a) Fluorine b) Fluorine c) 7 electrons d) MgF2 e) Less non-metallic

10. This question refers to the elements of the Periodic Table with atomic numbers from 3 to 18. Some of the elements are shown by letters, but the letters are not the usual symbols of the element:

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

Which of these elements are:
a) noble gases?     b) halogens?
c) alkali metals?    d) elements with valency 4?
Ans. a) H and P are noble gases.     b) G and O are halogens
c) A and I are alkali metals              d) D and L are elements with valency 4.

11. An element has 2 electrons in its M shell.
a) What is its atomic number?
b) State its position in periodic table
c) Is it metal or non-metal? [2016]
d) State the name assigned to this group.
Ans. (a) 12
(b) Group II A/2 and period 3
(c) It is a metal
(d) Alkaline earth metals

12. An element A has atomic number 14. To which period does this element belong and how many elements are there in this period?
Ans. Electronic configuration : 2, 8, 4.
        The element belongs to period 3.
        There are 8 elements in this period.

13. Answer the following in respect of element 3115P . 
(i) Give its electronic configuration.
(ii) To which group and period does it belong?
(iii) What is its valency?
(iv) Is it metal or non-metal?
(v) Is it a reducing agent or oxidising agent?
(vi) Give its formula with chlorine.
Ans. (i) 2, 8, 5
(ii) The element belongs to period 3 and group VA/15
(iii) 3
(iv) It is a non-metal
(v) It is an oxidizing agent
(vi) PCl3 / PCl5

14. An element X belong to 4th period and 17th group, state
(i) no of valence electrons in it
(ii) name of the element
(iii) name the family to which it belong
(iv) write the formula of the compound formed when it reacts with 2713Y .
Ans. (i) Seven
(ii) Bromine
(iii) Halogens
(iv) YX3

15. The electronic configuration of an element T is 2, 8, 8, 1.
(a) What is the group number of T?
(b) What is the period number of T?
(c) How many valence electrons are there in an atom of T?
(d) What is the valency of T?
(e) Is it a metal or a non-metal?
Ans. (a) IA/ 1
(b) Period 4
(c) 1
(d) 1
(e) Metal

16. Consider the section of periodic table given below :

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

Note:-
(1) In this table some elements are given in their own symbol and position in the periodic table.
(2) Other elements are shown with letters this is ‘A’, ‘D’, ‘E’, ‘G’, ‘L’ and ‘M’.
You must see the position of the element in the periodic table.
Now answer the following questions, with reference to the table :
(i) Which is most electronegative ?
(ii) Compare the size of the atoms of Li and M. In which case will it be less ?
(iii) Write the formula of the compound between ‘A’ and ‘L’
(iv) Name the alkaline earth metal in period 3.
Ans. (i) M
(ii) ‘Li’ will have a greater atomic size as compared to ‘M’ because as we move across the period from left to right atomic size decreases as nuclear charge increases.
(iii) A2L
(iv) Mg

Summary

• Summary chart of periodic properties in periods and groups.

PERIODIC TABLE - PERIODIC PROPERTIES AND VARIATIONS OF PROPERTIES

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