One isotope of iodine differs from another in __________ .


a. the number of protons
b. the number of electrons
c. the number of neutrons
d. atomic number

Verified step by step guidance

1. Understand that isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons.
2. Recall that the number of protons in an atom defines the element and is known as the atomic number.
3. Recognize that the number of electrons in a neutral atom is equal to the number of protons, and isotopes of an element have the same electron configuration.
4. Identify that the difference between isotopes of the same element is due to the variation in the number of neutrons.
5. Conclude that the correct answer is the option that states isotopes differ in the number of neutrons.

Key Concepts

Isotopes

Isotopes are variants of the same chemical element that have the same number of protons but differ in the number of neutrons. This difference in neutrons results in different atomic masses but does not change the chemical properties significantly.

Atomic Number

The atomic number is the number of protons in the nucleus of an atom and defines the element. It remains constant for all isotopes of a given element, distinguishing one element from another.

Neutrons and Atomic Mass

Neutrons are neutral particles in the nucleus that contribute to the atomic mass but do not affect the charge. Variations in neutron number among isotopes cause differences in atomic mass and nuclear stability.