# How does a barium atom become a barium ion with a 2^+ charge?

Dec 19, 2016

See explanation below.

#### Explanation:

Basically, an atom becomes an ion when it "steals" electrons from another atom or when another atom "steals" electrons from it. Barium becomes an ion with a ${2}^{+}$ charge when it reacts with another atom of another element that steals 2 electrons from it.

For instance, in the reaction represented below, solid barium reacts with hydrochloric acid to produce aqueous barium chloride and hydrogen gas: $B {a}_{\left(s\right)} + 2 H C {l}_{\left(a q\right)} \to B a C {l}_{2 \left(a q\right)} + {H}_{2 \left(g\right)}$
In this redox reaction, barium starts as a neutral solid but becomes an aqueous ion with a ${2}^{+}$ charge. Hydrogen begins as an aqueous ion with a $1 +$ charge and becomes a neutral gas. Thus, two hydrogen atoms steal a total of two electrons from one barium atom, resulting in the formation of neutral hydrogen gas and a barium ion with a ${2}^{+}$ charge.

An atom is oxidized when it has one or more electrons stolen from it.
An atom is reduced when it steals one or more electrons from another atom.