Match the following.

(a) Isotopes of cobalt – Treatment of cancer

Explanation:

Isotopes of cobalt are used in the treatment of thyroid cancer and some cancer which occurs rarely.

(b) Valency of nitrogen – Three

Explanation:

The atomic number of nitrogen = 7

The electronic configuration of ₇N= 2,5

The valency of nitrogen is 3 because it combines with other element and receives three electros to complete the outermost shell (8-5=3)

(c) Non – metal – Receives electrons

Explanation:

Non- metals tend to receive electrons to complete their outermost shell. Outermost shell is the only shell which participates in the chemical reaction.

(d) Metal – loses electrons

Explanation:

Metals tend to loose electrons to complete their outermost shell.

(e) Valency – Electrons in the outermost orbit

Explanation:

Valency is the number of electrons in the outermost shell.

For example, carbon has 4 electrons in the outermost shell. Thus, the valency of carbon is 4.