Atomic theory

Question 1

Democritus

Answer 1

all matter could be divided until a single particle is reached, which he called the atom. He proposed that atoms are different sizes, in constant random motion, and separated by space.

Question 2

Aristotle

Answer 2

He believed that all matter was made of earth, air, water, fire, and had qualities of dry, cold, wet, and hot.

Question 3

J.J Thomson

Answer 3

Proposed that atoms contain negative charges, since atoms are neutral the rest of the atom is positively charged, negatively charged electrons are evenly distributed throughout the atom. (Plum pudding model, he discovered the electron)

Question 4

Ernest Rutherford

Answer 4

Proposed that the centre of an atom has a positive charge called the nucleus, the nucleus is surround by a cloud of electron, most of the atom is empty space. (Rutherford also discovered the proton)

Question 5

James Chadwick

Answer 5

Discovered neutrons, and proposed that the nucleus contains protons and neutrons, proton mass = neutron mass, electrons circle around the nucleus, number of protons = number of electrons.

Question 6

Niels Bohr

Answer 6

Proposed that electrons orbit the nucleus, each electron has a definite amount of energy, the further from the nucleus the greater the electrons energy, electrons can jump to and from orbits, they release energy as light when the do, each orbit holds a certain number of electrons (2,8,8)