Write the name for Ba3(PO4)2
A) barium (III) phosphite
B) barium (II) phosphite
C) barium phosphate
D) tribarium phosphorustetraoxide
E) barium phosphite
The correct answer and explanation is :
The correct answer is:
C) Barium Phosphate
Explanation:
To determine the name of Ba₃(PO₄)₂, we need to follow the systematic rules for naming ionic compounds.
Step 1: Identify the Cation (Ba³⁺)
- The first part of the formula is Ba, which represents Barium.
- Barium is an alkaline earth metal in Group 2 of the periodic table, meaning it always has a +2 charge (Ba²⁺).
Step 2: Identify the Anion (PO₄³⁻)
- The second part of the formula is (PO₄)₂, which is the phosphate ion (PO₄³⁻).
- Phosphate is a polyatomic ion with a charge of -3.
Step 3: Balance the Charges
- The total charge of the compound must be neutral.
- Since barium has a +2 charge (Ba²⁺) and phosphate has a -3 charge (PO₄³⁻), we need 3 Ba²⁺ ions to balance with 2 PO₄³⁻ ions, creating the formula Ba₃(PO₄)₂.
Step 4: Naming the Compound
- The cation (Ba²⁺) name is simply “Barium” because it is from Group 2, and Group 2 metals do not require a Roman numeral.
- The anion (PO₄³⁻) is “Phosphate” (not “Phosphite,” which is PO₃³⁻).
- When combining the two, the name remains Barium Phosphate.
Why the Other Options Are Incorrect:
- A) Barium (III) phosphite – Incorrect because barium does not form a +3 charge, and “phosphite” is PO₃³⁻, not PO₄³⁻.
- B) Barium (II) phosphite – Incorrect because “phosphite” (PO₃³⁻) is the wrong anion.
- D) Tribarium phosphorus tetraoxide – Incorrect because ionic compounds do not use prefixes like “tri-” or “tetra-” for naming.
- E) Barium phosphite – Incorrect because “phosphite” (PO₃³⁻) is the wrong anion.
Thus, the correct name for Ba₃(PO₄)₂ is Barium Phosphate.