Match the following columns. Column I (Nobles gases) Column II (Electronic configuration) (i) Helium (a) 2 , 8 (ii) Neon (b) 2 , 8 , 8 (iii) Argon (c) 2 (iv) Krypton (d) 2 , 8 , 8 , 18

(i) The electronic configuration of helium is 2 . Helium atoms have 2 electrons and the shell structure is 2 . (ii) The electronic configuration of neon is 2 , 8 . Neon has atomic number 10 , so a neon atom has 10 protons in its nucleus and therefore 10 electrons. (iii) The electronic configuration of argon is 2 , 8 , 8 . Atomic number of argon is 18 . (iv) The electronic configuration of krypton is 2 , 8 , 8 , 18 . Krypton is a chemical element with the symbol Kr and atomic number 36 . Column I (Nobles gases) Column II (Electronic configuration) (i) Helium (a) 2 (ii) Neon (b) 2 , 8 (iii) Argon (c) 2 , 8 , 8 (iv) Krypton (d) 2 , 8 , 8 , 18

Match the following columns. Column I Column II (i) A polar covalent compound (a) CO 2 (ii) A non-polar covalent compound. (b) HCl (iii) A gaseous molecule containing single covalent bond (c) Oxygen (iv) A gaseous molecule with double covalent bonds and lone pairs of electrons. (d) Chlorine

(i) HCl is a polar covalent compound as the chloride ion is more electronegative than hydrogen ion. (ii) CO 2 is a non-polar covalent compound because it has a linear, symmetrical structure, with 2 oxygen atoms of equal electronegativity pulling the electron density from carbon at an angle of 180 degrees from either direction. (iii) Chlorine is a gaseous molecule containing single covalent bond. Two chlorine atoms can share 1 electron each to form a single covalent bond. (iv) Oxygen is a gaseous molecule with double covalent bonds and lone pairs of electrons. It is a diatomic gas. Column I Column II (i) A polar covalent compound (b) HCl (ii) A non-polar covalent compound. (a) CO 2 (iii) A gaseous molecule containing single covalent bond (d) Chlorine (iv) A gaseous molecule with double covalent bonds and lone pairs of electrons. (c) Oxygen

What do you understand by a lone pair of electrons?

The pair of electrons that are left in the valence shell without forming covalent bonds are known as lone pairs of electrons. They affect the shape of the molecule and sometimes help in the formation of other molecules.

Give a reason for the following: Ionic compounds have a high melting point.

Ionic compounds have high melting point because, there is a strong electrostatic force of attraction between the oppositely charged ions, that is, there is a strong electrostatic force of attraction between the cation and the anion.

E M B I B E

All in One - ICSE Chemistry>Chapter 2 - Chemical Bonding>CHAPTER EXERCISE>Q 13

EASY

10th ICSE

IMPORTANT

Earn 100

How many electrons are required for the octet structure of chlorine?

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Important Questions on Chemical Bonding

HARD

10th ICSE

IMPORTANT

All in One - ICSE Chemistry>Chapter 2 - Chemical Bonding>CHAPTER EXERCISE>Q 14

Elements

X, Y

and

Z

have atomic number

6, 9

and

12

respectively. Which one of the given elements forms an anion and cation, respectively?

EASY

10th ICSE

IMPORTANT

All in One - ICSE Chemistry>Chapter 2 - Chemical Bonding>CHAPTER EXERCISE>Q 15

Which pair of elements given below will undergo covalent bond formation?

EASY

10th ICSE

IMPORTANT

All in One - ICSE Chemistry>Chapter 2 - Chemical Bonding>CHAPTER EXERCISE>Q 16

Match the following columns.

Column I (Nobles gases)	Column II (Electronic configuration)
(i) Helium	(a) $2, 8$
(ii) Neon	(b) $2, 8, 8$
(iii) Argon	(c) $2$
(iv) Krypton	(d) $2, 8, 8, 18$

EASY

10th ICSE

IMPORTANT

All in One - ICSE Chemistry>Chapter 2 - Chemical Bonding>CHAPTER EXERCISE>Q 17

Match the following columns.

Column I	Column II
(i) A polar covalent compound	(a) ${CO}_{2}$
(ii) A non-polar covalent compound.	(b) $HCl$
(iii) A gaseous molecule containing single covalent bond	(c) Oxygen
(iv) A gaseous molecule with double covalent bonds and lone pairs of electrons.	(d) Chlorine