how does the electronic configuration of barium compare with that of calcium?

Answer 1

Barium and Calcium are both in Goup 2/IIA. So they both have 2 electrons in their outer shell. But, check out the periodic table, Barium is in Period 6, but Calcium is only in Period 4. Barium has an atomic number of 56, so it has 56 protons and electrons, while Calcium has atomic number 20 which means only 20 electrons and protons.

If you follow the 2n2 rule and the aufbau chart, you can check out exactly how the electrons are arranged.

ps - since Barium has more levels, obviously its electrons are further out from the nucleus! The rule Matt F is thinking of applies to atoms moving across the periods from left to right, not to atoms moving down the groups from top to bottom.

Answer 2

The both have two electrons, but since barium contains more protons, it's electrons are closer to the nucleus.