Electron config. of monatomic ion of strontium

Question

What is the complete electron configuration for a monatomic ion of strontium? What is the charge? How would I figure this out? Thank you sm!

Answer 1

Start with the electron configuration for the neutral atom

[Kr]5s2

In forming an ion, it will lose the most loosely held (outermost energy level/valence) electrons first. Sr has 2 electrons in energy level 5. Those are the ones it will lose because when those are gone, the remaining electrons are in lower energy levels therefore closer to the nucleus and requiring more energy to remove.

A neutral strontium atom has 38 protons and 38 electrons. If it forms an ion by losing 2 electrons then it has two more protons than electrons so its charge is +2