history of the atom Flashcards
1
Q
Who was Democritus?
A
Democritus
- ancient Greek philosopher
- he thought that matter was made up of particles called atomos which is the Greek word for indivisible.
- his theory was disproved for 2000 years.
2
Q
Who was James Dalton?
A
James Dalton: FATHER OF ATOMIC THEORY
- a school teacher in England
- worked with gases and considered Democritus’ theory that particles are atoms
- he described atoms as tiny spheres that were able to bounce around with perfect elasticity.
- PROBLEM: -unable to explain the electrical nature of matter
Like charges:
Repel
Unlike charges:
Attract
3
Q
Who was J.J. Thompson?
A
J.J. Thompson:
- atom had a positive core and negatives embedded in this
- model is called plum pudding model or raisin bun model
- a problem some solution allows electricity to flow where electrons are able to move.
4
Q
Who was Ernest Rutherford?
A
Ernest Rutherford: FATHER OF NUCLEAR AGE
- designed an experiment using radium; an element that releases positively charged particles.
- placed a piece of gold foil in front of the beam surrounded by a screen to detect the path of particles.
- his model had a positive nucleus and the electron cloud around the nucleus.
5
Q
Who was Sir James Chadwick?
A
Sir James Chadwick
- the nucleus contains another particle with no charge called a neutron.
- this particle had approximately the same mass as the proton but the electron is very small; it takes 2000 electrons to have the same mass as 1 proton/neutron
6
Q
Who was Neils Bohr?
A
Neils Bohr
-refined Rutherford’s idea by adding that the electrons are in orbit and each orbit can only hold a set number of electrons.
7
Q
Order of people
A
D.D.T.R.C.B
Democritus Dalton Thompson Rutherford Chadwick Bohr
8
Q
who is the father of atomic theory?
A
James Dalton
9
Q
who is the father of nuclear age?
A
Ernest Rutherford?
