P.1.2 Vocabulary

average of protons & neutrons

• Atomic mass

• Atomic number

• Proton

identifies an element.

The protons

• Atomic number

• Atomic mass

• Electrons

negative charge

they determine the reactivity of groups of elements in the periodic table

• Protons

• Electrons

• Neutron

Positive charge, identifies element (atomic number)

• Proton

• Electron

• Neutron

Center of atom; protons & neutrons

• Nucleus

• Electron

• Proton

• Electron

Smallest unit of a compound

• molecule

• electron

• proton

substance reacts chemically

• reactive

• nonreactive

• proton

substance does not react chemically

• nonreactive

• reactive

• neutron

hard, shiny, malleable, and ductile, conducts electricity

• metals

• nonmetals

• reactive

brittle and poor conductors of electricity

• nonmetals

• metals

• reactive