Consider the following atoms in which X represents the chemical symbol of the element: (4.4, 4.5) ¹⁶₈X ¹⁶₉X ¹⁸₁₀X ¹⁷₈X ¹⁸₈Xc. Which atoms have the same mass number?

Verified step by step guidance

1. Identify the mass number for each atom. The mass number is the superscript number before the chemical symbol X.
2. List the mass numbers for each atom: 115, 116, 115, 115, 117.
3. Compare the mass numbers to find which atoms have the same mass number.
4. Notice that the mass number 115 appears multiple times.
5. Conclude that the atoms with mass numbers 115 are the ones that have the same mass number.

Key Concepts

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This results in different mass numbers for the isotopes. For example, in the question, the isotopes of element X are represented with varying mass numbers, indicating they are isotopes of the same element.

Mass Number

The mass number of an atom is the total number of protons and neutrons in its nucleus. It is represented as the upper left number in the isotope notation (e.g., ¹⁶ in ¹⁶₈X). Understanding mass numbers is crucial for identifying isotopes and determining which atoms have the same mass number.

Atomic Number

The atomic number is the number of protons in the nucleus of an atom and determines the element's identity. It is represented as the lower left number in the isotope notation (e.g., ₈ in ¹⁶₈X). While isotopes of an element share the same atomic number, they differ in mass number due to variations in neutron count.