Atoms, Ions, Molecules

Atom● The basic unit of matter● Structure:

○ protons- have a + charge○ neutrons- have no charge

■ protons and neutrons form the nucleus○ electrons- have a - charge

■ move around the nucleus in energy levels

Element● Atoms with the same characteristics● Have the same # of protons

○ protons give atoms their identity○ changing # of electrons = ion○ changing # of neutrons = isotope

● Carbon, oxygen, nitrogen, and hydrogen make up 96% of your body

Element

Isotope

Electrons● The cause of all chemical

reactions and bonds.● Octet rule: Atoms want 8

electrons in their outer energy level○ the first energy level only

wants 2

Electrons● Atoms gain or lose electrons to fulfill the

octet rule● Molecule- Two or more atoms bonded

together● Compound- Two or more elements bonded

together

Ionic Bonds● A bond between ions● Ion- an atom that gained or lost an electron● Cation- atom that loses an electron, has a +

charge● Anion- atom that gains an electron, has a -

charge

Ionic Bonds

Ionic Bonds

Ionic Bonds● The cation and anion are attracted to each

other and bond.

Covalent Bonds● Atoms bond by sharing electrons● Shared electrons fill the outer energy levels