Compare the properties of electron, proton and neutron.

How will you find the valency of chlorine, sulphur and magnesium?

If number of electrons in an atom is 8 and number of protons is also 8, then (i) what is the atomic number of the atom? and (ii) what is the charge on the atom?

With the help of Table 4.1, find out the mass number of oxygen and sulphur atom.

For the symbol H, D and T tabulate three fundamental particles found in each of them.