To determine the correct chemical formula for magnesium nitride, we need to consider the valencies (or oxidation states) of magnesium (Mg) and nitrogen (N).
1. Valency of Magnesium (Mg): Magnesium is in Group 2 of the periodic table and has a valency of +2. This means each magnesium atom donates two electrons.
2. Valency of Nitrogen (N): Nitrogen is in Group 15 (or VA) of the periodic table and has a valency of -3. This means each nitrogen atom accepts three electrons.
To form a neutral compound, the total positive charge from magnesium atoms must equal the total negative charge from nitrogen atoms. Here are the steps to calculate the formula:
3. Balancing the Charges:
- If we have three magnesium atoms, each contributing a +2 charge, we get a total charge of [tex]\(3 \times (+2) = +6\)[/tex].
- To balance this, we need nitrogen atoms contributing a total negative charge of -6. Since each nitrogen atom has a -3 charge, we need two nitrogen atoms to achieve [tex]\(-3 \times 2 = -6\)[/tex].
4. Combining the Atoms:
- The smallest whole number ratio of magnesium to nitrogen that balances the charges is 3:2.
- Thus, three magnesium atoms combine with two nitrogen atoms.
Therefore, the correct formula for magnesium nitride is:
[tex]\[ Mg_3N_2 \][/tex]
Hence, the correct answer is:
A. [tex]\( Mg_3N_2 \)[/tex]
