1. Which electron configuration could represent a

strontium atom in an excited state?

Answer:2,8,18,7,3

Strontium has 38 electrons, adding up those numbers should make 38

Explanation:

The normal electronic configuration of strontium is 2,8,18,8,2, during excitation 1 electron is lost to the outermost shell from the inner shell carrying 8 electrons.

The proton number of an element corresponds with its electronic configuration, the electron at the outermost shell determines how reactive such element will be.

Most alkali metals are very reactive metals which strontium is one