Question

Five atoms are labelled from A to E.

Atoms	Mass No.	Atomic No.
A	40	20
B	19	9
C	7	3
D	16	8
E	14	7

(a) Which one of these atoms:
(i) contains 7 protons,
(ii) has an electronic configuration 2, 7?
(b) Write down the formula of the compound formed between C and D.
(c) predict which are: (i) metals, (ii) non-metals?

Answer 1

(a) (i) E
     (ii) B
(b) C2D
(c) A and C are metals while B, D and E are non -metals.