Which of the following shows the correct number of atoms of each element in the formula Mg(NO3)2?

• A. Mg: 2, N: 4, O: 12
• B. Mg: 1, N: 2, O: 6
• C. Mg: 1, N: 1, O: 3
• D. Mg: 2, N: 2, O: 6

Answer: (B)

Verified step by step guidance

1. Identify the elements present in the formula Mg(NO3)2. The elements are magnesium (Mg), nitrogen (N), and oxygen (O).
2. Look at the subscript outside the parentheses, which is 2. This means the entire group (NO3) is multiplied by 2.
3. Count the number of atoms of each element inside the parentheses: N has a subscript of 1 (implied), and O has a subscript of 3.
4. Multiply the number of atoms inside the parentheses by the subscript outside: N atoms = 1 \times 2, O atoms = 3 \times 2.
5. Count the Mg atoms, which is not inside the parentheses and has no subscript, so Mg atoms = 1.