The chemical formula for lithium phosphide is Li3P.
The Correct Answer and Explanation is:
Correct Answer:
The chemical formula for lithium phosphide is Li₃P.
Explanation:
Lithium phosphide is an ionic compound formed from lithium and phosphorus. To correctly write its chemical formula, we must first understand the charges of the ions involved and how they combine to create a neutral compound.
Step 1: Identify the ions
- Lithium (Li) is an alkali metal in Group 1 of the periodic table. Alkali metals form cations with a +1 charge. Therefore, the lithium ion is written as Li⁺.
- Phosphorus (P) is a nonmetal found in Group 15 of the periodic table. Nonmetals in this group tend to form anions with a -3 charge. Therefore, the phosphide ion is written as P³⁻.
Step 2: Balance the charges
For an ionic compound to be stable, the total positive and negative charges must balance each other out. Lithium has a +1 charge, while phosphide has a -3 charge. To balance the charges:
- We need three lithium ions (Li⁺), giving a total positive charge of +3.
- We need one phosphide ion (P³⁻), providing a total negative charge of -3.
This way, the sum of charges is zero, satisfying the requirement for a neutral ionic compound.
Step 3: Write the formula
The correct ratio of lithium to phosphide is 3:1, so the formula becomes Li₃P.
Step 4: Confirm the formula
- Total positive charge: 3 × (+1) = +3
- Total negative charge: 1 × (-3) = -3
- The overall charge is 0, confirming that the compound is neutral.
Thus, the correct chemical formula for lithium phosphide is Li₃P. This formula represents the simplest whole-number ratio of ions that results in a stable, neutral compound.
