In Mendeleev's periodic table elements with atomic numbers 18, 35 belongs to which group?

Options

A. Group zero, I
B. Group zero, III
C. Group zero,
D. Group zero, VII

Explanation

To determine the groups of the elements with atomic numbers 18 and 35 in Mendeleev's periodic table, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements**:
- The element with atomic number 18 is Argon (Ar).
- The element with atomic number 35 is Bromine (Br).

2. **Determine the Electronic Configuration**:
- For Argon (Ar):
- The electronic configuration is 2, 8, 8 (K, L, M shells).
- For Bromine (Br):
- The electronic configuration is 2, 8, 7.

3. **Analyze the Valency**:
- Argon has a full outer shell (8 electrons in its outermost shell), which makes its valency 0. This means Argon is stable and does not readily react with other elements.
- Bromine has 7 electrons in its outermost shell, which means it needs one more electron to achieve a full outer shell. Therefore, its valency is 1 (it can accept one electron).

4. **Determine the Groups**:
- In Mendeleev's periodic table, elements with a valency of 0 (like Argon) belong to Group 0 (Noble gases).
- Elements with a valency of 1 (like Bromine) belong to Group 7 (Halogens).

5. **Conclusion**:
- Therefore, the elements with atomic numbers 18 and 35 belong to Group 0 and Group 7, respectively.

### Final Answer:
- Argon (atomic number 18) belongs to Group 0.
- Bromine (atomic number 35) belongs to Group 7.