Atomic Theory . What do I need to know for the test?. Democritus. 460 BC-created the 1 st Atomic Theory of Matter (not modern atomic theory however) HIS THEORY Matter is composed of empty space through which atoms move Atoms are solid, homogeneous, indestructible, and indivisible
What do I need to know for the test?
Dalton revived Democritus’s ideas in the 19th century. Much time has passed.
That means that the plumb pudding model was wrong and there was a small dense center to an atom called a NUCLEUS!
When an electron falls from an excited state to the ground state, light is emitted….
At any given time, an electron can be found somewhere within its electron cloud. (90% of the time)