Page 191 - Chemistry

b) W 2O 3
27. i) Delocalized electrons
ii) Mobile ions
iii) Mobile ions

28. - Sodium has a larger raius than aluminium
- Aluminium has more protons than sodium hence a more effective nuclear charge
than sodium
29. a) 2.5
b) Q Group 1 ½, Period 4 ½
R Group 2 ½, Period 3 ½
30. Ethanol contains molecules 1 which are not1 responsible for electrical conductivity. (2
mks)
31. a (i) Q
(ii) R 
32. (a) K and N because they have the same number of electrons on their outermost energy level
(b) L 2O 7 
(c) L 1 because it has 7 electrons on the outermost energy level or reacts by gaining electrons
or the ionic radius is larger than the atomic radius (½mk)
33. a) Formula; J 5G 2 √1

b) E form ironic structures due to ionic bonding in its oxide. While G form molecular
structure due to covalent bonding in it oxide

Chemical families

1. a) - Non- metallic group
- Ionic radius larger than atomic radius
b) X – has smallest atomic radius hence more electronegative
2. To prevent filament from burning out. Provides an atmosphere in which burning cannot occur
i.e. inert atmosphere
3. a) Halogens
(b) X & Y
(c) Z is the largest atom with the highest number of energy levels occupied by electrons.
The longer an atom is the higher the forces of attraction that hold the molecules of the
element together
(d) 3Z (g) + 2Fe (s) FeZ 3(s)

(e) The blue litmus paper turned red that bleached. This is because it dissolves in water to form\
-1
an acid and bleaching solution of HO
4. (i) Down the group an extra energy level is added
(ii) In group x elements form ions by ionizing the outer energy levels
(iii) A cross the period an extra proton is added which increased he nuclear attraction force
(iv) BF 2
(v) – Ionic /electrovalent
- Involves loosing & gaining of electrons
(vi) G, F,E
-E has smallest atomic radius hence protons can attract an electron easier than in G
5. R – has the smallest atomic √ ½ size hence its outermost electrons are more strongly held to the
nucleus resulting in high √ ½ value of ionization energy
6. - Add dilute nitric acid to lead (u) carbonate
√
1
PbCO 3(s) + 2HNO 3(aq) Pb(NO 3) 2(aq) + CO 2(g) + H 2O(l)
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