Two small numbers beside an element symbol tell you everything about its nucleus: how many protons it has, and how many particles in total. From those, the rest follows by subtraction.
A nuclide is written with the nucleon number on top and the proton number below, before the element symbol. The proton number is the number of protons, the number of neutrons is the nucleon number minus the proton number, and in a neutral atom the electrons equal the protons.
The proton number (Z) is the number of protons; the nucleon number (A) is the number of protons plus neutrons. A nuclide is written with A on top and Z below, before the symbol.
In a neutral atom the number of electrons equals the number of protons.
Change the proton and neutron counts and watch the nuclide notation update.
Four quick checks. Each correct answer earns XP and lights this skill on your star map.
The proton number of an atom is...
The nucleon number is...
The number of neutrons in a nucleus is...
In a neutral atom, the number of electrons equals the number of...
The two numbers give the protons and the total, and neutrons follow by subtraction.
An atom has nucleon number 23 and proton number 11. Find the numbers of protons, neutrons and electrons.
The bottom number is the proton number Z and the top number is the nucleon number A. The neutron number is not written directly. Find it by subtracting: neutrons = A minus Z.
Unlocks once the four checks above are done. Worth more XP, written in the style of Paper 2.
An aluminium atom has nucleon number 27 and proton number 13. Its number of neutrons is...
A nucleus has 11 protons and a nucleon number of 23. The number of neutrons is...
A neutral atom has 8 protons. The number of electrons it has is...
Nuclide notation is mapped. Keep the chain going.