I NEED HELP Now write the abbreviated electron configuration for calcium. However, substitute [Ar] for the 1st 18 electrons of calcium. What is the electron configuration now?

[Ar]4s²

Explanation:

The electronic configuration of calcium is given as follows;

1s²2s²2p⁶3s²3p⁶4s²

The electronic configuration of argon, Ar is 1s²2s²2p⁶3s²3p⁶

Given, that there is a similarity be tween the electronic configuration of all the shells of the an atoms of argon and an atom calcium, except for the added valence shell electrons in calcium, the electronic configuration of calcium can be represented by the symbol of an atom of argon, followed by the electonic configuration of the valence shell as follows

The electronic configuration of calcium with argon as base = [Ar]4s².

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.