The electronic configuration of Calcium is-

Options

A. 2, 8, 2
B. 2, 8, 8
C. 2, 8, 8, 2
D. 2, 8, 8, 4

Answer

To determine the electronic configuration of Calcium, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Atomic Number**:
- The atomic number of Calcium (Ca) is 20. This means that Calcium has 20 electrons.

2. **Fill the Electron Shells**:
- We fill the electron shells according to the Aufbau principle, which states that electrons occupy the lowest energy orbitals first. The order of filling is:
- 1s, 2s, 2p, 3s, 3p, 4s, etc.

3. **Distribute Electrons in Shells**:
- **1s**: Can hold a maximum of 2 electrons. So, we fill 2 electrons in 1s.
- Configuration so far: 1s²
- **2s**: Can also hold a maximum of 2 electrons. Fill 2 electrons in 2s.
- Configuration so far: 1s² 2s²
- **2p**: Can hold a maximum of 6 electrons. Fill 6 electrons in 2p.
- Configuration so far: 1s² 2s² 2p⁶
- **3s**: Can hold a maximum of 2 electrons. Fill 2 electrons in 3s.
- Configuration so far: 1s² 2s² 2p⁶ 3s²
- **3p**: Can hold a maximum of 6 electrons. Fill 6 electrons in 3p.
- Configuration so far: 1s² 2s² 2p⁶ 3s² 3p⁶
- **4s**: Can hold a maximum of 2 electrons. Fill 2 electrons in 4s.
- Final configuration: 1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

4. **Summarize the Configuration**:
- The complete electronic configuration of Calcium is: **1s² 2s² 2p⁶ 3s² 3p⁶ 4s²**.

5. **Count the Electrons in Each Shell**:
- 1st shell (n=1): 2 electrons (1s²)
- 2nd shell (n=2): 8 electrons (2s² 2p⁶)
- 3rd shell (n=3): 8 electrons (3s² 3p⁶)
- 4th shell (n=4): 2 electrons (4s²)

### Final Answer:
The electronic configuration of Calcium is **1s² 2s² 2p⁶ 3s² 3p⁶ 4s²**.