Among the elements with atomic number 9, 20, 17and 36 which is highly electropositive ?

Options

A. Element with atomic number 9
B. Element with atomic number 36
C. Element with atomic number 17
D. Element with atomic number 20

Answer

To determine which element among those with atomic numbers 9, 20, 17, and 36 is the most electropositive, we will analyze their electronic configurations and stable oxidation states.

### Step 1: Identify the Elements
- Atomic number 9 corresponds to Fluorine (F).
- Atomic number 20 corresponds to Calcium (Ca).
- Atomic number 17 corresponds to Chlorine (Cl).
- Atomic number 36 corresponds to Krypton (Kr).

### Step 2: Write the Electronic Configurations
1. **Fluorine (F)**:
- Atomic number 9:
- Electronic configuration: \(1s^2 2s^2 2p^5\)

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

3. **Chlorine (Cl)**:
- Atomic number 17:
- Electronic configuration: \(1s^2 2s^2 2p^6 3s^2 3p^5\)

4. **Krypton (Kr)**:
- Atomic number 36:
- Electronic configuration: \(1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^{10} 4p^6\)

### Step 3: Determine the Stable Oxidation States
- **Fluorine (F)**:
- Tends to gain 1 electron to achieve a stable configuration (F⁻).

- **Calcium (Ca)**:
- Tends to lose 2 electrons to achieve a stable configuration (Ca²⁺).

- **Chlorine (Cl)**:
- Tends to gain 1 electron to achieve a stable configuration (Cl⁻).

- **Krypton (Kr)**:
- Noble gas, does not typically form ions, hence stable as Kr.

### Step 4: Identify the Most Electropositive Element
Electropositivity refers to the ability of an element to donate electrons. The more easily an element can lose electrons, the more electropositive it is.

- Among the elements analyzed:
- Fluorine and Chlorine are non-metals and tend to gain electrons, thus they are not electropositive.
- Calcium is a metal and tends to lose electrons easily, making it electropositive.
- Krypton is a noble gas and does not lose electrons.

### Conclusion
The most electropositive element among the given options is **Calcium (Ca)**, which corresponds to atomic number 20.

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