Hendley - Protons, Neutrons, Electrons (WiP)

The top number is the atomic number (Z) and corresponds to the protons.

The chemical symbol used to represent the element. First letter is always capitalized. Second letter (if present) is lower-case.

Name of the element.

The atomic mass is the weighted average of all naturally-occurring isotopes. Decimal because it's a weighted average.

On the Periodic Table is the Average Atomic Mass.

If rounded to a whole number, it is called the Mass Number (A).

The Mass number is needed for calculating protons, neutrons and electrons.

Protons are equal to the Atomic number.

To be neutral, electrons are also equal to the atomic number.

The Mass Number = protons + neutrons

The Atomic Number = protons

So, # of neutrons = mass number (A) - atomic number (Z)