3.1.1.1 - Fundamental particles

Atom

Made of protons, neutrons, electrons

Proton mass and charge

Relative mass: 1

Relative charge: +1

Neutron mass and charge

Relative mass: 1

Relative charge: 0

Electron mass and charge

Relative mass: 1/2000

Relative charge: -1

Electron movement

Move around nucleus in orbitals, which take up most of atom’s volume

Nucleus

• Contain most of atom’s mass

• Small diameter compared to whole atom

• Contains protons + neutrons

Negative ions have ____ electrons than protons

more

Positive ions have ____ electrons than protons

fewer

Isotope

Atoms of same element with same number of protons but different number of neutrons

Isotopes have same properties because same electron configuration, and that is what determines properties

Plum pudding model

Was initially thought that atoms contained sphere of +ve charge, with small -ve charges distributed evenly within it

Electron shell model

Atom consists of small, dense, central nucleus, surrounded by orbiting electrons in shells