In the long form of the periodic table, ________
group elements can release maximum amount of
energy by the addition of electron into is valence
shell.

Answer

To solve the question about which group of elements in the long form of the periodic table can release the maximum amount of energy by the addition of an electron into their valence shell, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Electron Affinity**:
- Electron affinity refers to the amount of energy released when an electron is added to a neutral atom in the gaseous state. Elements with high electron affinity release more energy when they gain an electron.

**Hint**: Remember that electron affinity is a measure of how much an atom wants to gain an electron.

2. **Identifying Groups in the Periodic Table**:
- The periodic table is organized into groups (columns) and periods (rows). The elements in Group 17 (or Group VIIA) are known as halogens.

**Hint**: Look for groups in the periodic table that are known for their high reactivity and tendency to gain electrons.

3. **Analyzing Group 17 (Halogens)**:
- The halogens include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements have high electronegativity and a strong tendency to gain electrons, resulting in a high release of energy (high electron affinity).

**Hint**: Recall that halogens are known for their reactivity and tendency to form negative ions (anions) by gaining an electron.

4. **Comparing with Other Groups**:
- Other groups, such as the noble gases (Group 18), have a complete valence shell and do not readily gain electrons, resulting in zero or very low electron affinity. Metals (Group 1 and 2) typically have low electron affinities as well.

**Hint**: Consider the stability of electron configurations when determining which groups are more likely to gain electrons.

5. **Conclusion**:
- Therefore, the group of elements that can release the maximum amount of energy by the addition of an electron into their valence shell is Group 17, the halogens.

**Final Answer**: In the long form of the periodic table, **Group 17** elements can release the maximum amount of energy by the addition of an electron into their valence shell.