Question

The position of three elements A, B and C in the periodic table are shown below:

Group 16	Group 17
B	A C

Giving reasons, explain the following:

(a) Element A is a non-metal.

(b) Element B has a larger atomic size than element C.

(c) Element C has a valency of 1.

Answer 1

(a) A is a non-metal because it can gain electrons easily, it has 7 valence electrons and forms negative ions to become stable.

(b) The atomic number of B is less than C, it has less nuclear charge, less force of attraction between protons in the nucleus and valence electrons, hence its size is bigger than C.

(c) Element ‘C’ has 7 valence electrons, it can gain 1 electron to become stable so its valency is 1.