(a) Which two of the following are isotopes of the same element: ³¹₁₆X, ³¹₁₅X, ³²₁₆X?

Verified step by step guidance

1. Identify the atomic number of each isotope, which is the subscript number (the number of protons) in the isotope notation.
2. Recognize that isotopes of the same element have the same atomic number but different mass numbers (the superscript number).
3. Compare the atomic numbers of the given isotopes: ³¹₁₆X, ³¹₁₅X, and ³²₁₆X.
4. Determine which isotopes have the same atomic number, indicating they are isotopes of the same element.
5. Conclude that the isotopes with the same atomic number are isotopes of the same element.

Key Concepts

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This means they occupy the same position on the periodic table and have the same atomic number, but their mass numbers differ. For example, carbon-12 and carbon-14 are isotopes of carbon, differing in their neutron count.

Atomic Number and Mass Number

The atomic number of an element is the number of protons in its nucleus, which defines the element itself. The mass number is the total number of protons and neutrons in the nucleus. In the notation ^A_ZX, A represents the mass number and Z represents the atomic number, helping to identify isotopes based on their mass differences.

Element Identification

Elements are identified by their atomic number, which corresponds to the number of protons. Isotopes of the same element will have the same atomic number but different mass numbers. In the given question, identifying which isotopes belong to the same element involves comparing their atomic numbers to determine if they are the same.