history of the atom

Question 1

What is a atom

Answer 1

All matter is composed of tiny particles called atoms, which are the smallest particle of an element. Made of a nucleus, electrons and protons and neutrons in the nucleus

Question 2

What are atoms observed with?

Answer 2

an instrument called scanning tunnelling microscope

Question 3

Democritus

Answer 3

Greek philosopher that Aristotle disagreed with. Believed atoms were indivisible (can’t be split apart) and indestructible. Lacked experimental support and chemical behaviour

Question 4

Thomson

Answer 4

Plum pudding model - depicts the electrons as negatively-charged particles embedded in a sea of positive charges

Question 5

Rutherford

Answer 5

Gold foil experiment where he shot Alpha particles through gold foil and looked at diffraction patterns. Proposed the atom was mostly empty space, and all positive charge and most of the mass is in the nucleus

Question 6

Niel Bohr

Answer 6

Believed Rutherfords experiment needed improvement. Said that an electron is found only in circular paths or orbits called energy levels

Question 7

Chadwick

Answer 7

Identifies neutrons which accounts for the total mass of the nucleus