Question

Number one and atom of element x contains 15 electrons and 16neutrons.

(a) State the mass number of X.
(ii) Write the electronic configuration of X.
(b) Write the formular of a chloride of X. Pliz , it's urgent. ​

Answer 1

a) 30.97

b) 3s² 3p²

I hope it's helps you

Answer 2

No of protons=No of electrons=15

Mass no:-No of neutrons+No of protons

`\\ \tt\longmapsto 15+16=31`

Now

It has atomic no 15 hence its Phosphorus(P)

Electronic configuration:-

`\\ \tt\longmapsto 1s^22s^22p^63s^23p^3`.

• Valency=3

Chloride formula:-

`\\ \tt\longmapsto XCl_3`

or.

`\\ \tt\longmapsto PCl_3`