Which of the following is correct order of Electron negativity:

Options

A. `Cs gt Rb gt Na`
B. `Li lt Be lt B`
C. `C lt N lt O`
D. `CI gt F gt Br`

Answer

To determine the correct order of electronegativity among the given elements, we need to follow these steps:

### Step 1: Understand the Concept of Electronegativity
Electronegativity is the tendency of an atom to attract shared electrons in a chemical bond. The trend in electronegativity is that it increases across a period (from left to right) and decreases down a group (from top to bottom) in the periodic table.

**Hint:** Remember that electronegativity increases across periods and decreases down groups.

### Step 2: Analyze the Given Elements
We need to analyze the groups and periods of the elements mentioned in the question. For example:
- **Group 1 Elements:** Cesium (Cs), Rubidium (Rb), Sodium (Na)
- **Group 2 Elements:** Lithium (Li), Beryllium (Be), Boron (B)
- **Period 2 Elements:** Carbon (C), Nitrogen (N), Oxygen (O)
- **Group 17 Elements:** Chlorine (Cl), Bromine (Br), Iodine (I)

**Hint:** Identify the position of each element in the periodic table to understand their relative electronegativities.

### Step 3: Determine the Electronegativity Order for Group 1
For Group 1 elements (Cs, Rb, Na):
- Cesium (Cs) is at the bottom of the group, so it has the lowest electronegativity.
- Sodium (Na) is higher up in the group, so it has a higher electronegativity than both Cs and Rb.
Thus, the correct order is Na > Rb > Cs.

**Hint:** Recall that as you move down a group, electronegativity decreases.

### Step 4: Determine the Electronegativity Order for Group 2
For Group 2 elements (Li, Be, B):
- As we move from left to right across the period, the electronegativity increases.
- Therefore, the correct order is B > Be > Li.

**Hint:** Use the left-to-right trend to determine the order of electronegativity.

### Step 5: Determine the Electronegativity Order for Period 2
For Period 2 elements (C, N, O):
- Again, moving from left to right, the electronegativity increases.
- Thus, the correct order is O > N > C.

**Hint:** Remember that electronegativity increases as you move to the right in a period.

### Step 6: Determine the Electronegativity Order for Group 17
For Group 17 elements (Cl, Br, I):
- Moving down the group, the electronegativity decreases.
- Therefore, the correct order is F > Cl > Br > I.

**Hint:** Note that fluorine is the most electronegative element.

### Conclusion
Based on the analysis:
1. The order for Group 1 is Na > Rb > Cs (incorrect in the question).
2. The order for Group 2 is B > Be > Li (correct).
3. The order for Period 2 is O > N > C (correct).
4. The order for Group 17 is F > Cl > Br (incorrect in the question).

Thus, the correct orders of electronegativity from the options provided are for Group 2 and Period 2.

**Final Answer:** The correct orders of electronegativity are for options 2 and 3.