Atomic Mass

Atomic mass is the mass of an atom of a chemical element. It is typically measured in atomic mass units (amu) and is approximately equivalent to the number of protons and neutrons in the atom.

Understanding Atomic Mass

Atomic mass is a key concept in chemistry and is crucial for understanding the behavior and properties of elements. It is determined by the total number of protons and neutrons in an atom's nucleus. The atomic mass is usually listed below the chemical symbol for an element on the periodic table.

Calculating Atomic Mass

The atomic mass of an element is calculated by adding the number of protons and neutrons in the nucleus. Since protons and neutrons have approximately the same mass, the atomic mass is approximately twice the number of protons. For example, the element carbon (C) has 6 protons and 6 neutrons, so its atomic mass is approximately 12 amu.

Isotopes and Atomic Mass

Many elements exist as multiple isotopes, which have the same number of protons but different numbers of neutrons. The atomic mass listed on the periodic table is the weighted average of the masses of all the isotopes of that element, taking into account their natural abundance.

Study Guide

Here are some key points to remember about atomic mass:

• Atomic mass is the mass of an atom of a chemical element, measured in atomic mass units (amu).
• It is determined by the total number of protons and neutrons in an atom's nucleus.
• The atomic mass of an element is usually listed below the chemical symbol on the periodic table.
• It is calculated by adding the number of protons and neutrons in the nucleus.
• The atomic mass listed on the periodic table is the weighted average of the masses of all the isotopes of that element.