The prperties which are not common to both groups 1 and 17 elements in the p-periodic table are:

Options

A. Electropositive character increase down the groups.
B. Reactivity decrease from top to bottom in these groups.
C. Atomic radii increase as the atomic number increase.
D. Electronegativity decreases on moving down the group

Answer

To determine the properties that are not common to both Group 1 (alkali metals) and Group 17 (halogens) elements in the p-periodic table, we will analyze the properties of these groups step by step.

### Step 1: Identify the Groups
- Group 1 elements include: Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb).
- Group 17 elements include: Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I).

### Step 2: Analyze Electropositive Character
- **Group 1**: Alkali metals are highly electropositive and their electropositive character increases down the group due to the increase in atomic size and decrease in ionization energy.
- **Group 17**: Halogens are not electropositive; they are electronegative and tend to gain electrons.
- **Conclusion**: Electropositive character is not common to both groups.

### Step 3: Analyze Reactivity Trends
- **Group 1**: Reactivity increases down the group as the tendency to lose an electron increases.
- **Group 17**: Reactivity decreases down the group because the ability to attract electrons decreases due to increased atomic size and shielding effect.
- **Conclusion**: Reactivity trends are not common to both groups.

### Step 4: Analyze Atomic Radii
- **Both Groups**: Atomic radii increase as you move down both groups due to the addition of electron shells.
- **Conclusion**: This property is common to both groups.

### Step 5: Analyze Electronegativity
- **Group 1**: Electronegativity decreases down the group as the electropositive character increases.
- **Group 17**: Electronegativity also decreases down the group due to the increase in atomic size and shielding effect.
- **Conclusion**: This property is also common to both groups.

### Final Conclusion
The properties that are not common to both Group 1 and Group 17 elements are:
1. Electropositive character increases down the group (common to Group 1 only).
2. Reactivity trends (increases for Group 1, decreases for Group 17).

### Summary of Properties Not Common:
- Reactivity trends are the primary property that is not common between Group 1 and Group 17 elements.