Test- Atoms and Scientists

Question 1

Democritus

Answer 1

400 BC
(Main-ish)
Greek philosopher, theorized that matter is made up of tiny particles called “atomos”

Question 2

Lavoisier​

Answer 2

1789
Closed system experiments (mercury oxidation experiment)
Theory of conservation of mass

Question 3

Proust​

Answer 3

1794
Law of definite proportions
Experiment: natural cupric carbonate vs synthetic as well as formation of CO2 from various reactions.​

Question 4

Dalton

Answer 4

1808
(main)
Billiard Ball model
Law of Multiple Proportions
1) All matter consists of indivisible particles called atoms
2) Atoms of the same element are similar in shape and mass but differ from the atoms of other elements
3) Atoms cannot be created or destroyed
4) Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms
5) Atoms of same element can combine in more than one ratio to form two or more compounds
6) The atom is the smallest unit of matter that can take part in a chemical reaction

Question 5

Crookes

Answer 5

1878
Crookes Tube (Cathode tube)
Studied cathode rays

Question 6

Goldstein

Answer 6

1886
Discovered proton
Discovered canal/anode rays

Question 7

Röntgen

Answer 7

1895
Accidental discovery of x-rays

Question 8

Thomson

Answer 8

1897
(main)
Plum pudding model
Discovered electron

Question 9

Becquerel

Answer 9

1896
Discovered radiation

Question 10

Curie

Answer 10

1898
Discovered radium and polonium
Coined the term “radioactivity”
Radioactivity originates within the atom itself

Question 11

Planck

Answer 11

1900
Proposed that energy is not emitted or absorbed continuously but in discrete units called quanta

Question 12

Millikan

Answer 12

1910
Oil drop experiment

Question 13

Rutherford

Answer 13

1911
Gold foil experiment
Discovered nucleus
Planetary model

Question 14

Bohr

Answer 14

1913
Bohr model
Proposed that electrons occupy specific orbits around the nucleus and can jump between these orbits

Question 15

de Broglie

Answer 15

1924
Electrons have wave-like properties
de Broglie hypothesis

Question 16

Schrödinger​

Answer 16

1926
Electron cloud model
Schrödinger​ equation

Question 17

Heisenberg​

Answer 17

1927
Uncertainty principle

Question 18

Law of Definite Proportions

Answer 18

Proust
Chemical compounds always combine in the same fixed ratios, regardless of where they come from or the amount.

Question 18

Chadwick

Answer 18

1932
Discovered neutron

Question 19

Law of Multiple Proportions

Answer 19

Atoms of different elements may combine with each other in a fixed, simple, whole number ratios to form compound atoms.​

Question 20

Oil drop experiment

Answer 20

Millikan
Precisely measured the charge of an electron by observing charged oil droplets between charged plates.

Question 21

de Broglie hypothesis

Answer 21

all matter has a wavelength associated with it, which can be calculated using a specific equation​

Question 22

Schrödinger equation

Answer 22

mathematical formula used to calculate the probability of finding an electron in a particular region around the nucleus

Question 23

Uncertainty principle

Answer 23

Heisenberg
a particle’s position and momentum cannot both be known exactly.