Question

(a) Write down the electronic configuration of (i) sodium atom, and (ii) chlorine atom.

(b) How many electrons are there in the outermost shell of (i) a sodium atom, and (ii) a chlorine atom ?

(c) Show the formation of NaCl from sodium and chlorine atoms by the transfer of electron(*).

(d) Why has sodium chloride a high melting point ?

(e) Name the anode and the cathode used in the electrolytic refining of impure copper metal.

Answer 1

(a) (i) Sodium – 2, 8, 1 (ii) Chlorine – 2, 8, 7

(b) (i) Sodium = 1 (ii) Chlorine = 7

(c)

(d) Sodium chloride has a high melting point because it is an ionic compound and these compounds are made of up of positive and negative ions. There is a strong force of attraction between the oppositely charged ions, so, a lot of heat energy is required to break this force of attraction and melt or boil the ionic compound.

(e) Anode: Thick block of impure copper metal; Cathode: Thin strip of p ure copper metal