Write the full electron configuration for Cl− . & What is the atomic symbol for the noble gas that also has this electron configuration?

Question

Write the full electron configuration for Cl^-.

1. full electron configuration:?

What is the atomic symbol for the noble gas that also has this electron configuration?

1. atomic symbol:?

Answer 1

Cl has atomic number 17, so it has 17 protons

Neutral Cl would thus have 17 electrons

Cl^- has one additional electrons, so it has 18 electrons.

1). Electron configuration for Cl^- is

1s2 2s2 2p6 3s2 3p6

2). Atomic symbol for noble gas with this same configuration is Ar (argon)