It seems like you're asking about the number of atoms in a molecule of magnesium nitrate (Mg(NO₃)₂). Let's break it down:

1. Understanding the Formula

* Mg(NO₃)₂: This is the chemical formula for magnesium nitrate. It tells us:

* There's one magnesium atom (Mg).

* There are two nitrate groups (NO₃).

* Each nitrate group contains one nitrogen atom (N) and three oxygen atoms (O).

2. Total Atoms

* Magnesium (Mg): 1 atom

* Nitrogen (N): 2 atoms (2 nitrate groups x 1 nitrogen per group)

* Oxygen (O): 6 atoms (2 nitrate groups x 3 oxygen per group)

3. Total: 1 + 2 + 6 = 9 atoms

Therefore, there are 9 atoms in one molecule of magnesium nitrate (Mg(NO₃)₂).