Question

What is the chemical formula of chromium (II) bromide?

Answer 1

Hint: As we know that in chemistry each element has a specific symbol in the periodic table. We first know the symbol of every element in the given molecule. The molecular formula of a chemical molecule depends on the symbol of the element and the number of the element count in the molecule. In written of chemical formula of molecule having some rules and regulation. In chemical formula, the symbol of metal atoms is written first and others are written next.

Complete step by step answer:
As we know that the chemical formula of chromium (II) bromide,
The symbol of chromium is \[{\text{Cr}}\]
The symbol of bromine is \[{\text{Br}}\]
We know that the oxidation state of chromium in chromium (II) bromide is \[ + 2\]. The oxidation state of bromine in chromium (II) bromide is \[ - 1\] .
That means in this molecule each chromium atom requires two bromine atoms to attain neutral and stability of the molecule.
\[ = ( + 2) + 2( - 1)\]
\[ \Rightarrow = ( + 2) + ( - 2) = 0\]
The sum of the oxidation number of the atoms in the formula is equal to zero.
Hence, the net charge of the molecule is zero that means neutral.
The chemical formula of chromium (II) bromide is \[{\text{CrB}}{{\text{r}}_{\text{2}}}\] .

Note: We also remember that the sum of the total oxidation number of the atom in the molecule is zero. If it is zero means the molecule in the stable state. If suppose, the sum of the oxidation number of the atom is greater than zero or positive value. That molecule is considered a cationic compound. In other cases, the sum of the oxidation number of the atom in the molecule is lesser than zero means that molecule is considered an ionic compound. The anionic and cationic compounds are less stable than neutral molecules. Because, ionic nature of the molecule, its reactivity is also greater than neutral molecules.