Question

1. c
2. f
3. neon

counting atoms

1. 5 cacl₂
2. 12 co
3. 16 2na₃po₄
4. h₂so₄
5. 4(nh₄)₂so₄

Explanation:

Step1: Analyze $H_2SO_4$

For $H_2SO_4$, there are 2 hydrogen (H) atoms, 1 sulfur (S) atom and 4 oxygen (O) atoms. So the total number of atoms is $2 + 1+4=7$.

Step2: Analyze $4(NH_4)_2SO_4$

First, expand $(NH_4)_2SO_4$. In $(NH_4)_2SO_4$, there are 2 nitrogen (N) atoms, $2\times4 = 8$ hydrogen (H) atoms, 1 sulfur (S) atom and 4 oxygen (O) atoms, making a total of $2 + 8+1 + 4=15$ atoms in one $(NH_4)_2SO_4$ unit. Since there are 4 units of $(NH_4)_2SO_4$, the total number of atoms is $4\times15 = 60$.

Answer:

1. 7
2. 60