Chemistry Year 9 - Chapter 2

atom

element

compound

atomic number shows

mass number shows

no. of protons and electrons must be the __________ to give ____ charge

electrons are held in shells by _________ __________

innermost electron shell can only hold ___ electrons

other electron shell can hold ___ electrons

Protons: same mass as ________, _______ charge

Neutrons: same mass as _____________, __________ charge

electrons: _________ mass, same no. as ___________, __________ charge