Chemistry, Third edition

434 ANSWERS TO EXERCISES AND REVISION QUESTIONS

(vii) (viii) (ix)

(x)

4B

(i)

(ii)2K(s)Cl 2 (g)2KCl(s) (or 2K+, 2Cl–(s))

4C

(i)

(ii)

(iii)

(iv)

(v)

4D

Lewis structures:

(i) (ii) (iii)

(iv) (v) (vi)

(vii) (viii)

(ix) (x)

Structural formulae:

(i) (ii) (iii)

(iv) (v) (vi)

(vii) (viii)

(ix) (x)

4E

Lewis structures:

(i) (ii)

(iii) (iv)

(v)

Structural formulae:

(i) (ii) (iii)

(iv) (v)

4F

(i)covalent (two non-metals)

(ii)ionic (metal non-metal)

(iii)covalent (two non-metals)

4G

(i) (ii) (iii)

4H

(i)0.6 (ii)1.4 (iii)0.4 (iv)0.5 (v)1.0.

Order: C––H+, C+–Cl–, Be+–H–, C+–O–, O––H+.

4I

These noble gases do not form covalent bonds with

other elements.

4J

(i)LiCl (ii)KF (iii)Al 2 S 3.

4K

(i) (ii)

where • is an electron donated from another atom, e.g.

Na+from Na+OH–.

4L

(i)

(ii)

Revision questions

4.1

(i) (ii) (iii)

(iv) (v)

4.2

(i) (ii) (iii)

(iv) (v)

whereshows electrons that have been donated by

other atoms.

4.3

(i)

(ii)

(iii)

(iv)

4.4Because the sodium atom has the electronic

structure 2.8.1, it loses only one electron to achieve the

stable electronic structure of neon.

4.5

(i) (ii)

(iii) (iv)

4.6

4.7 (i) (ii)

4.8

(i) (ii) (iii)

4.9Si–Br

4.101.8, ionic.

4.11

(i) (ii)

Unit 5

Exercises

5A

Li has to lose one electron only in order to achieve a

stable electronic structure. Be and B have to lose two

and three electrons, respectively. This takes a great deal

more energy than for Li.

5B

(i) (ii) 4

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