The atomic number of an element X is 17. Predict :
(a) Its valency.
(b) Whether it is a metal or non-metal.
(c) Its relatively atomic size with respect to other members in the group.
Ans. (a) Valency is 1 (Electronic configuration 2, 8, 7).
(b) It is a non-metal. (Tendency to accept electron as the outermost orbit has 7 electrons.)(c) Atomic size is relatively smaller with respect to the other members in a group.