Question

for an element x it is given that atomic number is 17 and mass number is 35.
a) write the electronic configuration of the element X.
b) find the valency.
c) what will be the formula of the compound formed between X and Y having valency 3​

Answer 1

electronic configuration= 1s²2s²2p⁶3s²3p⁶4s²3d⁷

valency= -1

YX3

Answer 2

X is Chlorine(Cl)
(a) 2 8 7
(b) 1-
(c) X3Y