An element X belongs to group 2 and period 3 of the periodic table. The chemical formulae of its nitrate, sulphate and phosphate respectively will be

Options

A. `X(NO_(3))_(2), XSO_(4), X_(3)(PO_(4))_(2)`
B. `XNO_(3), XSO_(4), XPO_(4)`
C. `X_(3)(NO_(3))_(2), X_(2)(SO_(4))_(2), X_(2)(PO_(4))_(3)`
D. `X(NO_(3))_(3), X_(2)(SO_(4))_(3), X_(2)(PO_(4))_(3)`

Explanation

To solve the problem, we need to determine the chemical formulae for the nitrate, sulfate, and phosphate of the element X, which belongs to group 2 and period 3 of the periodic table.

### Step-by-Step Solution:

**Step 1: Identify the Element**
- The element X is in group 2 and period 3. The only element that fits this description is Magnesium (Mg).

**Step 2: Determine the Valency of Magnesium**
- Magnesium (Mg) has an atomic number of 12, and its electronic configuration is 1s² 2s² 2p⁶ 3s².
- Magnesium has 2 valence electrons (in the 3s orbital).
- To achieve a stable electronic configuration, magnesium will lose these 2 electrons, giving it a valency of +2.

**Step 3: Write the Chemical Formula for Nitrate (NO₃⁻)**
- The nitrate ion has a charge of -1 (NO₃⁻).
- To balance the +2 charge from magnesium, we need 2 nitrate ions.
- Therefore, the formula for magnesium nitrate is:
\[ \text{Mg(NO}_3\text{)}_2 \]

**Step 4: Write the Chemical Formula for Sulfate (SO₄²⁻)**
- The sulfate ion has a charge of -2 (SO₄²⁻).
- Since the charge of sulfate is -2, it balances perfectly with the +2 charge of magnesium.
- Thus, the formula for magnesium sulfate is:
\[ \text{MgSO}_4 \]

**Step 5: Write the Chemical Formula for Phosphate (PO₄³⁻)**
- The phosphate ion has a charge of -3 (PO₄³⁻).
- To balance the +2 charge from magnesium, we need 3 magnesium ions to balance the -3 charge of phosphate.
- Therefore, the formula for magnesium phosphate is:
\[ \text{Mg}_3(\text{PO}_4)_2 \]

### Final Answer:
- The chemical formulae of magnesium's nitrate, sulfate, and phosphate are:
- Nitrate: \(\text{Mg(NO}_3\text{)}_2\)
- Sulfate: \(\text{MgSO}_4\)
- Phosphate: \(\text{Mg}_3(\text{PO}_4)_2\)