Masses of Atoms

Using a chart of student test grades as an example, curious chemists learn how to calculate weighted averages. They apply this knowledge to elements on the periodic table. As practice in calculating average atomic masses, learners...

Discover the relationship between mass number, atomic number, and the makeup of the atom. The video instructor explains how to determine the number of each subatomic particle from the atomic and mass number. She demonstrates multiple...

The amount of information you can learn about an element from the periodic table is amazing! Young scientists learn how to interpret the atomic number and atomic mass. Using a carbon atom as an example, the instructor describes the...

Scientists created a new measurement, the atomic mass unit, which is defined as carbon 12 = 12amu. So why isn't carbon listed as having exactly 12 amu on the periodic table? An installment from the Socratica chemistry playlist answers...

Check your understanding of how to use the atomic number and the mass number to represent different isotopes. [9:43]

Discover the significance of the atomic number and mass number. A video lesson describes the relationship between the two numbers and the subatomic particles. The instructor leads several examples that use the two numbers to determine...

[Free Registration/Login may be required to access all resource tools.] Shows the calculation of mass number.

Recognize the atomic number and mass number of an atom and how they are linked to the electrons, protons and neutrons of an atom. [2:05]

How to use the atomic number and the mass number to represent different isotopes. [9:44]

Some isotopes are unstable, or radioactive, meaning they will decay over time and turn into another isotope or stable element. In the interactive simulation, participants manipulate elements to create isotopes and gather information....