Write a formula for the compound that forms between rubidium and each polyatomic ion: Part A Carbonate. Express your answer as a chemical formula. Part B Phosphate. Express your answer as a chemical formula. Part C Hydrogen phosphate. Express your answer as a chemical formula. Part D Acetate. Express your answer as a chemical formula.
The Correct Answer and Explanation is:
Here are the correct chemical formulas for the compounds formed between rubidium (Rb) and each of the polyatomic ions:
Part A: Carbonate (CO₃²⁻)
Rubidium (Rb) has a charge of +1, and the carbonate ion (CO₃²⁻) has a charge of -2. To balance the charges, two rubidium ions are required for every carbonate ion. Therefore, the chemical formula is:
Rb₂CO₃
Explanation:
Rubidium is an alkali metal, so it forms a cation (Rb⁺) with a charge of +1. Carbonate is a polyatomic ion with a charge of -2. To neutralize the charges, two rubidium cations are needed to balance the -2 charge from the carbonate ion. Hence, the formula is Rb₂CO₃.
Part B: Phosphate (PO₄³⁻)
The phosphate ion (PO₄³⁻) has a charge of -3, and rubidium (Rb) has a charge of +1. To balance the charges, three rubidium ions are required for every phosphate ion. Therefore, the chemical formula is:
Rb₃PO₄
Explanation:
Rubidium’s +1 charge and phosphate’s -3 charge need to be balanced. Since one Rb⁺ ion cannot balance the -3 charge of phosphate, we need three rubidium ions to neutralize the charge. Hence, the formula is Rb₃PO₄.
Part C: Hydrogen phosphate (HPO₄²⁻)
The hydrogen phosphate ion (HPO₄²⁻) has a charge of -2, and rubidium (Rb) has a charge of +1. To balance the charges, two rubidium ions are required for every hydrogen phosphate ion. Therefore, the chemical formula is:
Rb₂HPO₄
Explanation:
The hydrogen phosphate ion has a -2 charge, and rubidium forms +1 cations. To balance the overall charge, two rubidium ions are needed. Therefore, the formula is Rb₂HPO₄.
Part D: Acetate (C₂H₃O₂⁻)
The acetate ion (C₂H₃O₂⁻) has a charge of -1, and rubidium (Rb) has a charge of +1. Since the charges are equal in magnitude, one rubidium ion will balance the charge of one acetate ion. Therefore, the chemical formula is:
RbC₂H₃O₂
Explanation:
Acetate is a negatively charged ion with a charge of -1, while rubidium forms a cation with a charge of +1. The charges are already balanced, so one rubidium ion combines with one acetate ion to form RbC₂H₃O₂.
In all these compounds, the key principle is ensuring that the total positive and negative charges balance out to form a neutral compound. The number of rubidium ions needed depends on the charge of the polyatomic ion involved.
