Question

which of the following correctly counts the atoms in ca₃(po₄)₂? 3ca, 2p, 4o 3ca, 4p, 6o 1ca, 2p, 4o 3ca, 2p, 8o

Explanation:

Step1: Count calcium atoms

The sub - script outside the parentheses for Ca is 3, so there are 3 Ca atoms.

Step2: Count phosphorus atoms

The sub - script for P inside the parentheses is 1 and the sub - script outside the parentheses is 2. So the number of P atoms is $1\times2 = 2$.

Step3: Count oxygen atoms

The sub - script for O inside the parentheses is 4 and the sub - script outside the parentheses is 2. So the number of O atoms is $4\times2=8$.

Answer:

3 Ca, 2 P, 8 O