Question 1:

Which of the following statements about isotopes is true?

Explanation: The correct answer is B) Isotopes have different numbers of neutrons. Isotopes are atoms of the same element that have different numbers of neutrons but the same number of protons and electrons.

Question 2:

What is an atomic mass unit (amu) used for?

Explanation: The correct answer is C) To measure the mass of an atom or particle. An atomic mass unit (amu) is a unit of mass used to express the mass of atomic and subatomic particles.

Question 3:

Which of the following elements has the greatest number of naturally occurring isotopes?

Explanation: The correct answer is C) Uranium. Uranium has the greatest number of naturally occurring isotopes, with a total of 15 known isotopes.

Question 4:

What is the atomic mass of an element based on?

Explanation: The correct answer is A) The average mass of all the naturally occurring isotopes of that element. The atomic mass of an element is a weighted average of the masses of its isotopes, taking into account their relative abundances.

Question 5:

Which of the following isotopes is commonly used as a reference for atomic mass?

Explanation: The correct answer is A) Carbon-12. Carbon-12 is commonly used as a reference isotope for atomic mass, and its atomic mass is defined as exactly 12 atomic mass units (amu).