11-02-2013, 04:28 PM
ATOMIC MODELS
ATOMIC MODELS.ppt (Size: 1.33 MB / Downloads: 24)
The atomic model has changed throughout the centuries, starting in 400 BC, when it looked like a billiard ball
Democritus
This is the Greek philosopher Democritus who began the search for a description of matter more than 2400 years ago.
He asked: Could matter be divided into smaller and smaller pieces forever, or was there a limit to the number of times a piece of matter could be divided?
Atomos
His theory: Matter could not be divided into smaller and smaller pieces forever, eventually the smallest possible piece would be obtained.
This piece would be indivisible.
He named the smallest piece of matter “atomos,” meaning “not to be cut.”
Dalton’s Theory
He deduced that all elements are composed of atoms. Atoms are indivisible and indestructible particles.
Atoms of the same element are exactly alike.
Atoms of different elements are different.
Compounds are formed by the joining of atoms of two or more elements.