Question

Write the electronic configuration of the element with atomic number 17. Indicate the valency of the element.

Answer 1

Atomic number is 17
So, the no. of protons and no. of electrons is 17.
Electronic configuration is
\[\ce{\underset{2}{K}   \underset{8}{L}   \underset{7}{M}}\]
Here, the outermost orbit has 7 electrons. In order to make it 8, the element will have to gain 1 electron. So, the valency of the element is 1.