Which is not similar characteristics(s) about the electronic configuration of Be, Mg, Ca?

Options

A. All the atojms have a pair of s-electrons in their outermost energy level
B. all the atoms contain a pair of p-electrons in their outermost energy level
C. All are alkaline earth metals
D. All are of secon group of the periodic table

Answer

To determine which characteristic of the electronic configuration of beryllium (Be), magnesium (Mg), and calcium (Ca) is not similar, we can analyze their electronic configurations step by step.

### Step 1: Identify the Electronic Configurations
- **Beryllium (Be)**: Atomic number = 4
- Electronic configuration: \(1s^2 2s^2\)

- **Magnesium (Mg)**: Atomic number = 12
- Electronic configuration: \(1s^2 2s^2 2p^6 3s^2\)

- **Calcium (Ca)**: Atomic number = 20
- Electronic configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2\)

### Step 2: Analyze the Similarities and Differences
- All three elements belong to Group 2 (alkaline earth metals) in the periodic table.
- They all have filled s-orbitals in their outermost shells:
- Be: 2 electrons in the 2s orbital
- Mg: 2 electrons in the 3s orbital
- Ca: 2 electrons in the 4s orbital
- None of these elements have electrons in their outermost p-orbitals:
- Be has no p-electrons.
- Mg has no p-electrons.
- Ca has no p-electrons.

### Step 3: Identify the Non-Similar Characteristic
Given the configurations:
- The key non-similar characteristic is that while all three have filled s-orbitals, they differ in the principal quantum number of their outermost shell.
- Beryllium has its outermost electrons in the 2nd shell, magnesium in the 3rd shell, and calcium in the 4th shell.

### Conclusion
The characteristic that is not similar among Be, Mg, and Ca regarding their electronic configuration is that they occupy different principal energy levels (n=2 for Be, n=3 for Mg, and n=4 for Ca).