` MgCl_2` is the formula for an ionic compound of magnesium and chlorine. If the charge on Cl is -1, then the charge on Mg must b

Options

A. `+2`
B. `+3`
C. `-2`
D. `-3`

Explanation

To determine the charge on magnesium (Mg) in the ionic compound MgCl₂, we can follow these steps:

### Step 1: Understand the composition of the compound
The formula MgCl₂ indicates that the compound consists of one magnesium ion (Mg²⁺) and two chloride ions (Cl⁻).

**Hint:** The subscript in the formula indicates how many of each ion are present in the compound.

### Step 2: Identify the charge on chloride ions
We are given that the charge on each chloride ion (Cl) is -1.

**Hint:** Remember that the charge of an ion can be determined from its position in the periodic table or common oxidation states.

### Step 3: Calculate the total negative charge
Since there are two chloride ions in MgCl₂, the total negative charge contributed by the chloride ions is:
\[ \text{Total negative charge} = 2 \times (-1) = -2 \]

**Hint:** Multiply the charge of one ion by the number of ions to find the total charge.

### Step 4: Determine the charge on magnesium
For the compound to be neutral, the total positive charge must equal the total negative charge. Therefore, the charge on magnesium (Mg) must be +2 to balance the -2 charge from the two chloride ions.

**Hint:** The overall charge of a neutral compound is zero, so the positive and negative charges must cancel each other out.

### Step 5: Conclusion
Thus, the charge on magnesium (Mg) in MgCl₂ is +2.

**Final Answer:** The charge on Mg must be +2.

---