Skip to main content
Ch.2 - Atoms, Molecules, and Ions
Chapter 2, Problem 25a

(a) Define atomic number and mass number.

Verified Solution

Video duration:
1m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Atomic Number

The atomic number is the number of protons found in the nucleus of an atom. It uniquely identifies an element and determines its position on the periodic table. For example, hydrogen has an atomic number of 1, indicating it has one proton. The atomic number also influences the chemical properties of the element.
Recommended video:
Guided course
02:10
Atom Structure

Mass Number

The mass number is the total number of protons and neutrons in an atom's nucleus. It is not the same as atomic mass, which is a weighted average of all isotopes of an element. For instance, carbon has a mass number of 12, which means it typically has 6 protons and 6 neutrons. The mass number helps in identifying isotopes of an element.
Recommended video:

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, resulting in different mass numbers. For example, carbon-12 and carbon-14 are isotopes of carbon, with mass numbers of 12 and 14, respectively. Isotopes can exhibit different physical properties and stability, influencing their applications in fields like medicine and archaeology.
Recommended video: