Science · Grades 8–8
Chemistry · Formula sheet
Rules, conditions and small examples in one printable reference.
Remember this
Atomic number and mass number
Atomic number counts protons; mass number counts protons plus neutrons.
neutrons = mass number − atomic number
62 − 27 = 35
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.