1. ATOMS THE BUILDING BLOCKS OF MATTER

2. The Greek Model • Democritus concluded that matter could not be divided into smaller and smaller pieces forever. • The smallest piece would be obtained and would be . • He named this smallest piece of matter an . • He hypothesized that atoms were _____ and made of the same material.

3. Dalton’s Model • All elements are composed of atoms. • Atoms of the same element are exactly _____. • Atoms of different elements are _______. • Compounds are formed by joining of atoms of _________ elements.

4. Thomson’s Model • The atom is made of a puddinglike positively charged material throughout which negatively charged (_______) electrons were scattered, like plums in a pudding!

5. Rutherford’s Model • Proposed that an atom is mostly empty space with a dense, positively charged ______in the center. • Negatively charged electrons were scattered outside nucleus.

6. Bohr Model • Electrons move in definite orbits around the nucleus. • These orbits, or __________, are located at certain distances from the nucleus.

7. Wave Model • Electrons do not move around an atom in a _______ path. • Scientists can only predict where an electron may be. • Location is based on how much _____ the electron has.

8. Modern Atomic Theory • Based on Rutherford’s Model, Bohr’s Model and wave mechanics. • An atom has a small, positively charged nucleus surrounded by a large region in which there are enough electrons to make the atom _______.