# What charge does the barium ion possess in the compound BaCl_2?

Jul 2, 2016

The Barium ion in this molecule would have $+ 2$ charge.

#### Explanation:

Barium is in the 6th energy level of the periodic table in the second column, with an electron configuration of $B a = \left[X e\right] 6 {s}^{2}$

Barium would lose two electrons to follow the Rule of Octet and become $B {a}^{+} 2 = \left[K r\right] 5 {s}^{2} 4 {d}^{10} 5 {p}^{6}$

The Barium ion is $B {a}^{+} 2$
The Chloride ion is $C {l}^{-} 1$

It takes two $- 1$ Chloride ions to balance the one $+ 2$ Barium ions to form the Barium Chloride molecule $B a C {l}_{2}$

Jul 2, 2016

$B a$ commonly forms a divalent ion, i.e. $B {a}^{2 +}$.

#### Explanation:

How do I know this? Well, for a start, barium is an alkaline earth metal, that commonly forms a $+ I I$ ion. Even if I didn't know this, I should know that $B r$, a halogen, commonly forms a $- I$ ion, and thus barium assumes a $+ I I$ oxidation state in $B a {X}_{2}$. Look at their positions on the Periodic Table: $\text{Group II metal}$ and $\text{Group VII non-metal}$.