Answer :

To determine the number of nitrogen atoms in the chemical formula [tex]\( \text{Ni} \left( \text{NO}_3 \right)_2 \)[/tex], follow these steps:

1. Break down the components of the formula [tex]\( \text{Ni} \left( \text{NO}_3 \right)_2 \)[/tex]:
- [tex]\( \text{Ni} \)[/tex] stands for Nickel.
- [tex]\( \left( \text{NO}_3 \right) \)[/tex] is a nitrate group.

2. Observe the subscript outside the parentheses, which indicates how many nitrate groups are present in the formula. In this case, the subscript is 2, meaning there are 2 nitrate groups.

3. Each nitrate group [tex]\(\text{NO}_3\)[/tex] contains one nitrogen atom.

4. Since there are 2 nitrate groups and each group has 1 nitrogen atom, multiply the number of nitrogen atoms per nitrate group by the number of nitrate groups:
[tex]\[ \text{Total number of nitrogen atoms} = 1 \text{ nitrogen atom/group} \times 2 \text{ groups} = 2 \text{ nitrogen atoms} \][/tex]

Therefore, the chemical formula [tex]\( \text{Ni} \left( \text{NO}_3 \right)_2 \)[/tex] contains 2 nitrogen atoms.

The correct answer is:
2