Atoms present in a molecule of heavy water are

Options

A. `""_(1)H^(1), ""_(8)O^(16)`
B. `""_(1)H^(2), ""_(8)O^(18)`
C. `""_(1)H^(2), ""_(8)O^(16)`
D. `""_(1)H^(1),""_(8)O^(18)`

Answer

To determine the atoms present in a molecule of heavy water, we need to analyze its chemical formula and the isotopes involved.

### Step-by-Step Solution:

1. **Identify the formula of heavy water**:
- The chemical formula for heavy water is \( D_2O \), where \( D \) represents deuterium, an isotope of hydrogen.

2. **Understand the composition of heavy water**:
- In heavy water, there are two deuterium atoms and one oxygen atom. Therefore, the composition can be summarized as:
- 2 atoms of deuterium (D)
- 1 atom of oxygen (O)

3. **Identify the isotopes**:
- Deuterium (\( D \)) is an isotope of hydrogen with an atomic mass of 2 (compared to protium, which has an atomic mass of 1).
- The oxygen atom in heavy water is typically the isotope with an atomic mass of 16, represented as \( O^{16} \).

4. **Summarize the atoms in heavy water**:
- Thus, the atoms present in a molecule of heavy water (\( D_2O \)) are:
- 2 deuterium atoms (D)
- 1 oxygen atom (O)

### Conclusion:
The atoms present in a molecule of heavy water are 2 deuterium atoms and 1 oxygen atom.