Which of the following best explains how boron-10 and boron-11 differ?

• A. They belong to different chemical elements.
• B. They have different numbers of neutrons.
• C. They have different numbers of electrons in a neutral atom.
• D. They have different numbers of protons.

Answer: (B)

Verified step by step guidance

1. Understand that boron-10 and boron-11 are isotopes of the same element, boron, which means they have the same number of protons but differ in the number of neutrons.
2. Recall that the atomic number (number of protons) defines the element, so both boron-10 and boron-11 have the same number of protons (5 for boron).
3. Recognize that the mass number (the number after the element name) represents the total number of protons and neutrons in the nucleus.
4. Calculate the number of neutrons by subtracting the atomic number from the mass number: Number of neutrons = Mass number - Number of protons.
5. Conclude that boron-10 and boron-11 differ because they have different numbers of neutrons, not because they differ in protons, electrons (in a neutral atom), or are different elements.