Which of the following is a correct statement?

Options

A. Boron is diagonally related to silicon
B. Elements of third period are known as bridge elements
C. There are sixteen groups and seven periods in extended form of period table
D. Fluorine has higher electron affinity than Chlorine

Answer

To determine which of the statements is correct, we will analyze each option step by step.

### Step 1: Analyze Option 1
**Statement:** Boron is diagonally related to silicon.

**Analysis:**
- Boron (B) is in Group 13, and Silicon (Si) is in Group 14 of the periodic table.
- Diagonal relationships occur between elements in different groups but in the same period or adjacent periods.
- Boron (Group 13) is indeed diagonally related to Silicon (Group 14) as they are adjacent in the periodic table.

**Conclusion:** This statement is **correct**.

### Step 2: Analyze Option 2
**Statement:** Elements of the third period are known as bridge elements.

**Analysis:**
- The third period consists of elements from Sodium (Na) to Argon (Ar).
- The term "bridge elements" typically refers to elements that have properties of both metals and non-metals, often seen in the second period.
- The third period elements are not commonly referred to as bridge elements.

**Conclusion:** This statement is **incorrect**.

### Step 3: Analyze Option 3
**Statement:** There are 16 groups.

**Analysis:**
- The modern periodic table has **18 groups**.
- Therefore, stating there are 16 groups is incorrect.

**Conclusion:** This statement is **incorrect**.

### Step 4: Analyze Option 4
**Statement:** Seven periods in the extended form of the periodic table.

**Analysis:**
- The extended periodic table indeed has **7 periods**.
- This statement is correct.

**Conclusion:** This statement is **correct**.

### Step 5: Analyze Option 5
**Statement:** Chlorine has higher electron affinity than fluorine.

**Analysis:**
- Fluorine (F) has a higher electron affinity than Chlorine (Cl) due to its smaller atomic size, which allows it to attract electrons more effectively.
- Therefore, the statement is incorrect.

**Conclusion:** This statement is **incorrect**.

### Final Summary
- The correct statements from the options are:
- **Option 1:** Boron is diagonally related to silicon. (Correct)
- **Option 4:** There are seven periods in the extended form of the periodic table. (Correct)

### Final Answer
The correct statements are: **1 and 4**.

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