Which of the following statements is correct about element `""_(8)^(17)A` and element `""_(17)^(37)B` ?

Options

A. A is more electronegative than B
B. A forms a positive ion and B forms a negative ion
C. A and B have the same number of neutrons
D. A and B have the same number of electrons.

Answer

To determine which of the statements about elements \( A \) and \( B \) is correct, we first need to analyze the given information about both elements:

1. **Identify the elements**:
- Element \( A \) has an atomic number of 8 and a mass number of 17.
- Element \( B \) has an atomic number of 17 and a mass number of 37.

2. **Determine the elements**:
- The element with atomic number 8 is Oxygen (O).
- The element with atomic number 17 is Chlorine (Cl).

3. **Evaluate the statements**:
- **Statement 1**: "A is more electronegative than B."
- Oxygen (A) is indeed more electronegative than Chlorine (B). This is true because electronegativity generally decreases from top to bottom in a group in the periodic table. Therefore, this statement is **correct**.

- **Statement 2**: "A forms a positive ion and B forms a negative ion."
- Both Oxygen and Chlorine are nonmetals. Nonmetals typically gain electrons to form negative ions, not positive ones. Therefore, this statement is **false**.

- **Statement 3**: "A and B have the same number of neutrons."
- To find the number of neutrons, we subtract the atomic number from the mass number:
- For Oxygen (A): Neutrons = Mass number - Atomic number = 17 - 8 = 9.
- For Chlorine (B): Neutrons = Mass number - Atomic number = 37 - 17 = 20.
- Since 9 is not equal to 20, this statement is **false**.

- **Statement 4**: "A and B have the same number of electrons."
- For neutral atoms, the number of electrons equals the atomic number:
- Oxygen has 8 electrons.
- Chlorine has 17 electrons.
- Since 8 is not equal to 17, this statement is **false**.

4. **Conclusion**:
- The only correct statement is that "A is more electronegative than B."

### Final Answer:
The correct statement is: **A is more electronegative than B.**

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