The number of electrons present in outermost shell of halogen is

Explanation

To determine the number of electrons present in the outermost shell of halogens, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Halogen Family**:
- The halogen family consists of elements in Group 17 of the periodic table. The main halogens are Fluorine (F), Chlorine (Cl), Bromine (Br), and Iodine (I).

2. **List the Atomic Numbers**:
- Fluorine (F) has an atomic number of 9.
- Chlorine (Cl) has an atomic number of 17.
- Bromine (Br) has an atomic number of 35.
- Iodine (I) has an atomic number of 53.

3. **Determine Electron Configuration**:
- Electrons fill energy levels (shells) in the order of increasing energy. The shells are labeled as K, L, M, N, O, etc.
- The maximum number of electrons that can fit in each shell is:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 18 electrons
- N shell: 32 electrons, and so on.

4. **Fill the Electrons for Each Halogen**:
- **Fluorine (F)**:
- K shell: 2 electrons
- L shell: 7 electrons (Total = 9)
- **Outermost shell (L)** has 7 electrons.
- **Chlorine (Cl)**:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 7 electrons (Total = 17)
- **Outermost shell (M)** has 7 electrons.
- **Bromine (Br)**:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 18 electrons
- N shell: 7 electrons (Total = 35)
- **Outermost shell (N)** has 7 electrons.
- **Iodine (I)**:
- K shell: 2 electrons
- L shell: 8 electrons
- M shell: 18 electrons
- N shell: 18 electrons
- O shell: 7 electrons (Total = 53)
- **Outermost shell (O)** has 7 electrons.

5. **Conclusion**:
- In all halogens (F, Cl, Br, I), the number of electrons in the outermost shell is consistently 7.

### Final Answer:
The number of electrons present in the outermost shell of halogens is **7**.