Which has zero oxidation number :-

Options

A. Cd
B. `Cl_(2)`
C. (1) & (2)
D. None

Answer

To determine which of the given options has a zero oxidation number, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Oxidation Numbers**:
- Oxidation number (or oxidation state) is a concept used to indicate the degree of oxidation of an atom in a chemical compound.
- Elements in their free (uncombined) state have an oxidation number of zero.

2. **Identify Free Elements**:
- Metals in their elemental form have an oxidation number of zero.
- Diatomic molecules (like Cl2, O2, N2, etc.) also have an oxidation number of zero.

3. **Analyze the Options**:
- Let's assume the options are:
- A: Cl2
- B: Na
- C: Cd
- D: O2
- Here, Cl2 (chlorine gas) and Cd (cadmium) are both in their elemental forms.

4. **Determine the Oxidation States**:
- For Cl2: Since it is a diatomic molecule in its elemental form, its oxidation number is 0.
- For Cd: As a metal in its elemental form, its oxidation number is also 0.
- If there are other options like Na or O2, Na (sodium) in its elemental form has an oxidation number of 0, and O2 (oxygen gas) also has an oxidation number of 0.

5. **Conclusion**:
- Based on the analysis, both Cl2 and Cd have a zero oxidation number. Therefore, the correct answer includes both these options.

### Final Answer:
The elements with zero oxidation number are **Cl2 and Cd**.