Electronic configuration of strontium

Electrons in each shell

Strontium has 38 electrons arranged as 2, 8, 18, 8, 2 across 5 shells, which is why it sits in period 5.

How to write it

Start from the previous noble gas core, written in square brackets, then add the remaining electrons in filling order. For strontium that gives [Kr] 5s².

Strontium at a glance

Other elements in group 2

Elements in the same group have the same number of outer electrons, which is why they behave alike.