In halogen, which of the following properties increase from iodine to fluroine

Options

A. Ionisation energy
B. Electronegativity
C. Bond length
D. Electron affinity

Answer

To answer the question regarding which properties increase from iodine to fluorine in the halogen group, we need to analyze the properties mentioned: ionization energy, electronegativity, bond length, and electron affinity.

### Step-by-Step Solution:

1. **Understanding the Halogen Group**:
- The halogens are located in Group 17 of the periodic table, which includes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).
- As we move from iodine (I) to fluorine (F), we are moving up the group.

2. **Analyzing Ionization Energy**:
- Ionization energy is the energy required to remove an electron from an atom.
- Generally, ionization energy increases as you move up a group in the periodic table due to decreasing atomic size and increasing effective nuclear charge.
- Therefore, ionization energy increases from iodine to fluorine.

3. **Analyzing Electronegativity**:
- Electronegativity is the tendency of an atom to attract electrons in a chemical bond.
- Similar to ionization energy, electronegativity increases as you move up the group.
- Thus, electronegativity also increases from iodine to fluorine.

4. **Analyzing Bond Length**:
- Bond length refers to the distance between the nuclei of two bonded atoms.
- As you move from iodine to fluorine, the size of the atoms decreases, leading to shorter bond lengths.
- Therefore, bond length decreases from iodine to fluorine.

5. **Analyzing Electron Affinity**:
- Electron affinity is the energy change that occurs when an electron is added to a neutral atom.
- Electron affinity generally becomes more negative (increases) as you move up the group.
- Hence, electron affinity increases from iodine to fluorine.

### Conclusion:
From the analysis, we conclude that the properties that increase from iodine to fluorine are:
- Ionization Energy (increases)
- Electronegativity (increases)
- Electron Affinity (increases)

The property that does not increase is bond length (it decreases).

### Final Answer:
The properties that increase from iodine to fluorine are:
- Ionization Energy
- Electronegativity
- Electron Affinity