Chemistry, Third edition

4 · BONDING BETWEEN ATOMS

Revision questions

62

4.1.Write Lewis symbols for the following atoms:

(i)Li (ii)B (iii)N (iv)O (v)Si.

4.2.Write Lewis symbols for the following ions:

(i)S^2  (ii)H (iii)P^3  (iv)Ca^2  (v)Br.

4.3.Use Lewis symbols to describe the reactions between the

following elements:

(i)Mg and S (ii)Ca and Br (iii)K and S (iv)Mg and N.

4.4.Why does sodium not form the Na^2 ion in its compounds?

4.5.Draw Lewis structures for the following molecules:

(i)H 2 S (ii)CF 4 (iii)I 2 (iv)PH 3.

4.6.Write a Lewis structure for F 2 CO (C is the central atom).

4.7.The ion BF 4 contains a coordinate bond. Write:

(i)the Lewis structure

(ii)the structural formula of the ion.

4.8.Draw Lewis structures for the following ions:

(i)ClO (ii)NO 2 (iii)NH 2

4.9.Use the electronegativity values in Box 4.6 to decide

which of the following bonds is the most polar:

(i)N–O (ii)P–Cl (iii)Si–Br.

4.10.What is the electronegativity difference between the

atoms Mg and N? Is the bond between these atoms likely to be

ionic or covalent?

4.11.Two Lewis structures exist for ozone (O 3 ), each of

which contains one double and one single bond:

(i) Write the structural formulae of both of the Lewis

structures.

(ii)The actual structure of ozone is a resonance hybrid of both

structures. Draw a diagram to show the structure of the

resonance hybrid.

DID YOU KNOW?

Sir Humphry Davywas an English scientist, who discovered metals such as potassium, sodium, bar-

ium, strontium, calcium and magnesium. His most famous invention was a safety lamp for use in coal

mines where the highly inflammable gas, methane, is often found. Davy first proposed the name for the

element with the symbol AI and called it alumium, but he changed his mind, a few years later, and called

italuminum. Many British users disliked this name, however, because it didn’t conform with the ‘ium’

ending given in the names of metals and adopted the name aluminium. Americans still prefer alu-

minum, which is why you will see this spelling in their textbooks.

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