Which one of the following does not increase while moving down the group of the periodic table ?

Options

A. Atomic radius
B. Metallic character
C. Valence
D. Number of shell in an element

Explanation

To solve the question "Which one of the following does not increase while moving down the group of the periodic table?", we will analyze the properties of elements as we move down a group in the periodic table.

### Step-by-Step Solution:

1. **Understanding the Properties**: We need to identify the properties that are typically considered when analyzing elements in a group. Common properties include atomic radius, metallic character, valency, and the number of electron shells.

2. **Analyzing Atomic Radius**: As we move down a group, the atomic radius increases. This is because additional electron shells are added, making the atom larger.

**Hint**: Remember that more shells mean a larger atomic size.

3. **Analyzing Metallic Character**: The metallic character of elements also increases as we move down a group. This is due to the increase in atomic size, which allows electrons to be lost more easily.

**Hint**: Consider how the ability to lose electrons relates to size and metallic character.

4. **Analyzing Valency**: Valency, which refers to the number of electrons an atom can lose, gain, or share, does not change as we move down a group. All elements in the same group have the same valency because they have the same number of electrons in their outermost shell.

**Hint**: Valency is determined by the outermost electrons, which remain constant within a group.

5. **Analyzing Number of Shells**: The number of electron shells does increase as we go down the group, as each subsequent element has an additional shell.

**Hint**: More shells are added with each period down the group.

6. **Conclusion**: From our analysis, we can conclude that the property that does not increase while moving down the group is **valency**.

Thus, the correct answer is **valency**.

### Final Answer: Valency does not increase while moving down the group of the periodic table.

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