Page 93 - ICSE Chemistry 8

C. Write the atomic number and mass number of the following elements.
Element Atomic number Mass number

Lithium __________________ __________________

Carbon __________________ __________________

Fluorine __________________ __________________

Magnesium __________________ __________________
Sulphur __________________ __________________

Potassium __________________ __________________

D. Write the number of protons, electrons and neutrons of the following elements.

Element Number of protons Number of electrons Number of neutrons

Beryllium __________________ __________________ __________________

Oxygen __________________ __________________ __________________

Sodium __________________ __________________ __________________
Aluminium __________________ __________________ __________________

Phosphorus __________________ __________________ __________________

Calcium __________________ __________________ __________________

E. Match the columns.

Column A Column B
1. Anode rays (a) Discovery of neutron
2. J. J. Thomson (b) Monovalent element

3. Magnesium (c) Trivalent element
4. James Chadwick (d) Consist of protons

5. Chlorine (e) Divalent element
6. Phosphorus (f) Plum pudding model

F. Choose the correct op on.
1. An atom consists of ______________.

(a) electrons (b) protons (c) neutrons (d) all of these
2. Cathode rays
(a) travel in straight line. (b) are produced from the anode in a discharge tube.
(c) consist of posi vely-charged par cles. (d) all of these.
3. _______________ suggested that electrons possess a specifi c amount of energy and are arranged
in a succession of energy levels.

(a) J.J. Thomson (b) James Chadwick (c) Niels Bohr (d) E. Rutherford

79