Year 11 Chemistry

Question 1

Democritus

Answer 1

460-370 BCE
proposed idea of atoms
different substances were composed of these

Question 2

John Dalton

Answer 2

Early 19th Century
Revived atomic theory
all matter is of atoms
atoms of elemtens are identical
cannot be destroyed
chemicals reactions: atoms manipulated

Question 3

JJ Thomson

Answer 3

Late 19th Century
Discovered electron
Proposed ‘plum pudding’ model
(sphere of positive charge with electrons

Question 4

Ernest Rutherford

Answer 4

Early 20th Century
Gold foil experiment
atomic nucleus- nuclear model
-mostly empty space
-small, dense positive nucleus
-electrons surrounding

Question 5

Niels Bohr

Answer 5

20th Cent
Electrons orbit specific paths
electrons can jump between energy levels

Question 6

Rule for atomic radius

Answer 6

Decreases down group
increases across period

Question 7

define forst ionisation energy (metals too)

Answer 7

energy requires to REMOVE 1 electron
metals want to lose electron because of empty valence shell

Question 8

Define and rules for electronegativity (metals)

Answer 8

ability to ATTRACT electrons
Increases across period
decreases down group
metals have low electronegativity

Question 9

physical properties vs chemical properties

Answer 9

physical:
-measured without changing composition (colour, state, melting point, density, solubility)
chemical:
- observed during a reaction (reactivity, ONCE REACTED CAN’T GO BACK, combustibility)