Atoms
All matter is made up of
An atom
He believed that atoms were Indivisible and indestructible
Democritus
Democritus
460-370
John Dalton's main ideas
1. Elements are made of atoms
2. Atoms of a given element are identical
3. Atoms of different elements differ in fundamental ways
4. Atoms of one element come combine with another to form a compound
5. Atoms retain its identity during a chemical reaction
An atom is the smallest part of an element that
Retains its identity during a chemical reaction
He Used experiments to develop the first modern atomic theory and Studied how elements combine in different ratios.
John Dalton
John Dalton
1766–1844
JJ Tompsons model and experiment
He passed an electric current through a glass tube filled with gas and it created a cathode ray. His model was the Plum Pudding model
Atom comes form the greek word
Atomos
He discovered the electron and discovered that they were negatively charged
JJ Thompson
JJ Thompson
(1856-1940)
Ernest Rutherford"s experiment
He shot a beam of positively charged particles a thin sheet of gold foil expecting it to go through. It bounced off.
The first to suggest the existence of an atom
Democritus
Discovered that the atom is mostly empty space and Positive charge is concentrated in a tiny area called the nucleus.
Ernest Rutherford
Neils Bohr
1913
Neils Bohr's model
His model was like planets orbiting the sun.
True or False: All atoms of the same element are alike
False
He said electrons move around the nucleus in energy levels/shells.
Niels Bohr
Neils Bohr studied under
Ernest Rutherford
Which one of Daltons ideas isn't true
The second one. Ex: isotopes