ATOMS THE LITTLE GIANTS OF ALL MATTER!!

Matter: all matter is made up of atoms. is anything that has a mass and a volume all matter has a specific density or arrangement of atoms that can be used to identify it.

John Dalton (aka Jack) 1. Atoms are the smallest form of matter 2. Atoms make up all matter 3. Atoms of the same element are the same 4. Atoms cannot be broken down 5. Atoms combine in specific ratios

Thomson: Discovered the electron First model of atom

Rutherford: Discovered presence of nucleus And protons Atom was mostly empty space

Chadwick: Discovers the neutron

Bohr: Suggested electrons move in energy Levels Presents model used today (although not completely accurate)

nucleus M shell L shell K shell +n+n

Electron cloud model Electron cloud Nucleus Neutron Proton

PERIODIC TABLE Elements: roughly 88 naturally occurring roughly 20 man made organized arrangement metals, nonmetals, metalloids, noble gasses pure substance

Element – pure Compound – 2 or more elements chemically combined homogeneous Mixture – 2 or more elements, compounds, or both physically combined. homogenous or heterogeneous

Proton: positively charged nucleus Neutron: no charge-neutral nucleus Electron: negatively charged energy shells

nucleus M shell L shell K shell +n+n

ATOMIC MASS: no. protons + neutron -- ATOMIC NUMBER: no. protons _________________________________ no. neutrons

Li At. Mass 7 -- At. # 3 ___________________________ 4 Protons: 3 Neutrons: 4 Electrons: 3* *all unbonded atoms are electrically and chemically neutral. # of + = # of e.

Isotopes: Atoms of the same element that Differ from each other by the number of Neutrons. Isotopes have the same Atomic number but A different Atomic Mass. 45 known isotopes of iodine I 127, 53 I 136, known isotopes of carbon C 12, 6 C 14, 6