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

1 Answer
Dec 19, 2016

See explanation below.


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: #Ba_((s)) + 2HCl_((aq)) -> BaCl_(2(aq)) + H_(2(g))#
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.