Question 1
(i)What is the common name given to the group VII elements?
(ii)Name the hydrides of the first two elements in group VII.
(iii)State three chemical properties of group VII elements [6 marks]
Copy and complete the following table
| Particles | Number of neutrons | Number of electrons | Number of Protons | Mass Number |
| W2+ | 12 | 24 | ||
| X2- | 8 | 16 | ||
| Y | 13 | 27 | ||
| Z | 12 | 11 | ||
[8 marks ]
- (i) Define each of the following processes:
- nuclear fission;
- nuclear fusion.
(ii) Give one use of each process in 1(c(i) [6 marks]
- (i)List three types of radiation that are produced during radioactivity.
- Arrange the radiations listed in 1(d)(i) in order of increasing:
- penetrating power;
- ionizing power. [5 marks]
ANSWER
The expected answers include:
(a) (i) Halogens
(ii) Hydrogen fluoride
Hydrogen chloride
(iii) – high electron affinity/strong oxidizing agents/electron acceptor
– highly electronegative;
– react with hydrogen to form acid;
– form salts with metals;
– react with alkalis to form salts;
– react with water to for acids;
– displacement of lower halogens from their acids/salts;
– react with hydrocarbon to form alkyl halides.
(b)
| Particles |
Number of neutrons |
Number of electrons |
Number of Protons |
Mass Number |
|
W2+ |
12 |
10 |
12 |
24 |
|
X2- |
8 |
10 |
8 |
16 |
|
Y |
14 |
13 |
13 |
27 |
|
Z |
12 |
11 |
11 |
23 |
(c)(i) I. Nuclear fission – splitting of a heavy nucleus into two smaller nuclei of similar
mass with the release of large amount of energy and radiations.
II. Nuclear fusion – combination of smaller nuclei to form a large nucleus with the
release of large amount of energy and radiation.
(ii) I. Used to generate electricity/nuclear bomb/production of new elements/production of
radioisotopes.
II. Used to produce nuclear weapon/atomic bomb/production of new elements/production radioisotopes.
(d) (i) alpha, beta, gamma
OR
α , β,
(ii) I. α < β <
increasing penetrating power
II. <β < α
increasing ionizing power
