Question

select the element that has one electron in the outer outermost shell and write its electronic configuration​

Answer 1

• (i) 19K (Potassium) is the element that has one electron in the outermost shell. (ii) 4Be (Beryllium) and 20Ca (Calcium) belong to the same group because they have same number of valence electrons.

Answer 2

Explanation:

the element which have one electron in the outermost shell is Sodium

its electronic configuration is 1s2 2s2 2p6 3s1