Ionic compounds may contain polyatomic ions, which consists of groups of atoms having an electrical charge. An example is magnesium nitrate. The formula of magnesium nitrate is

Options

A. `MgNO_3`
B. `Mg_(2)NO_3`
C. `Mg(NO_3)_2`
D. `Mg_2(NO_3)_2`

Explanation

To determine the formula of magnesium nitrate, we need to follow these steps:

### Step 1: Identify the ions involved
- Magnesium (Mg) is an alkaline earth metal that typically loses 2 electrons to form a cation with a +2 charge (Mg²⁺).
- Nitrate (NO₃) is a polyatomic ion with a -1 charge (NO₃⁻).

### Step 2: Determine the number of nitrate ions needed
- Since magnesium has a +2 charge and each nitrate ion has a -1 charge, we need two nitrate ions to balance the +2 charge from magnesium.
- Therefore, the formula will require 2 NO₃⁻ ions.

### Step 3: Write the formula
- Combine the magnesium ion and the two nitrate ions. The formula for magnesium nitrate will be written as:
- Mg(NO₃)₂

### Final Answer
The formula of magnesium nitrate is **Mg(NO₃)₂**.

---