Question

n ionic compound is named rubidium arsenate. complete the table to determine the number of ions of each type in one formula unit of the compound. enter a negative sign before negative numbers. positive numbers do not need a positive sign.
ion\tcharge of one ion\ttotal charge of ion(s) in compound\tnumber of ion(s) in compound
rubidium\tyellow box\tyellow box\tyellow box
arsenate\tyellow box\tyellow box\tyellow box
*in one formula unit
what is the formula for the ionic compound?
yellow dropdown\tyellow dropdown

Explanation:

Step1: Determine Rubidium Ion Charge

Rubidium (Rb) is in Group 1, so its ion charge is \( +1 \).

Step2: Determine Arsenate Ion Charge

Arsenate is \( \text{AsO}_4^{3-} \), so charge is \( -3 \).

Step3: Balance Charges

Let \( x \) = number of \( \text{Rb}^+ \), \( y \) = number of \( \text{AsO}_4^{3-} \). Total charge: \( x(+1) + y(-3) = 0 \). Solve: \( x = 3y \). Let \( y = 1 \), then \( x = 3 \).

Step4: Fill Table for Rubidium

• Charge of One Ion: \( +1 \)
• Total Charge: \( 3(+1) = +3 \)
• Number of Ions: \( 3 \)

Step5: Fill Table for Arsenate

• Charge of One Ion: \( -3 \)
• Total Charge: \( 1(-3) = -3 \)
• Number of Ions: \( 1 \)

Step6: Write Formula

Formula is \( \text{Rb}_3\text{AsO}_4 \) (3 \( \text{Rb}^+ \), 1 \( \text{AsO}_4^{3-} \)).

Table Filling:

Ion	Charge of One Ion	Total Charge of Ion(s) in Compound	Number of Ion(s) in Compound
Arsenate	\( -3 \)	\( -3 \)	\( 1 \)

Formula:

\( \text{Rb}_3\text{AsO}_4 \)

Answer:

(Table and Formula):

Table:

• Rubidium: Charge \( +1 \), Total Charge \( +3 \), Number \( 3 \)
• Arsenate: Charge \( -3 \), Total Charge \( -3 \), Number \( 1 \)

Formula: \( \boldsymbol{\text{Rb}_3\text{AsO}_4} \)