Question

What is the main difference between isotopes of the same element?

• A. Number of protons
• B. Number of neutrons
• C. Number of electrons
• D. Atomic number

Hint:

Isotopes of an element differ in the number of neutrons they contain, which affects their atomic mass but not their chemical behavior.

Answer 1

The Correct Option is B

Step 1: Understanding isotopes.
Isotopes are variants of the same element that have the same number of protons (atomic number) but differ in the number of neutrons. This difference in neutrons results in a different atomic mass but does not affect the chemical properties of the element.
Step 2: Explanation of options.
- (A) Number of protons: Isotopes of the same element have the same number of protons (this defines the element).
- (B) Number of neutrons: The key difference between isotopes of the same element is the number of neutrons.
- (C) Number of electrons: In isotopes, the number of electrons remains the same because they are neutral atoms.
- (D) Atomic number: The atomic number is the same for all isotopes of the same element, as it is determined by the number of protons.
Step 3: Conclusion.
The main difference between isotopes is the number of neutrons.
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