Proton Number
The atomic number (or proton number) is the number of protons in the nucleus of an atom
The symbol for atomic number is Z , its called Z because in German number is called Zahl that starts with z in German , Zahl defines number , the meaning is number
It is also the number of electrons present in a neutral atom and determines the position of the element on the Periodic Table
Mass Number
The Nucleon number (or mass number) is the total number of protons and neutrons in the nucleus of an atom
The symbol for nucleon number is A , cause in German the word Atomgewicht starts with A , in English called atomic number
The nucleon number minus the proton number gives you the number of neutrons of an atom
Note that protons and neutrons can collectively be called nucleons.
The atomic number and mass number of an element can be shown using atomic notation
The Periodic Table shows the elements together with their atomic (proton) number at the top and relative atomic mass at the bottom - there is a difference between relative atomic mass and mass number, but for your exam, you can use the relative atomic mass as the mass number (with the exception of chlorine)
