C and Si are placed in the same group, because

Options

A. both form chlorides with chlorine
B. both react with hydrogen
C. both have name number of electrons in their outermost orbit
D. both form oxide with oxygen

Explanation

**Step-by-Step Solution:**

1. **Identify the Elements:**
- The elements in question are Carbon (C) and Silicon (Si).

2. **Determine the Atomic Numbers:**
- Carbon has an atomic number of 6.
- Silicon has an atomic number of 14.

3. **Write the Electronic Configurations:**
- For Carbon (C):
- The electronic configuration is 1s² 2s² 2p².
- For Silicon (Si):
- The electronic configuration is 1s² 2s² 2p⁶ 3s² 3p².

4. **Identify the Valence Electrons:**
- Carbon has 4 valence electrons (2 in the 2s orbital and 2 in the 2p orbital).
- Silicon also has 4 valence electrons (2 in the 3s orbital and 2 in the 3p orbital).

5. **Determine the Group Number:**
- The group number in the periodic table corresponds to the number of valence electrons.
- Both Carbon and Silicon belong to Group 14 (IV A) because they both have 4 valence electrons.

6. **Conclusion:**
- Carbon and Silicon are placed in the same group because they have the same number of valence electrons, which is 4.

**Final Answer:**
C and Si are placed in the same group because they both have the same number of electrons in their outermost shell (4 valence electrons).

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