Atomic Structure And Periodic Table

Question 1

Atoms

Answer 1

Make up all substances and are the smallest part of an element

Question 2

Compounds

Answer 2

Contain 2 or more elements chemically combined together

Question 3

Mixture

Answer 3

Two or more elements or compounds not chemically combined

Question 4

Mixture separation techniques

Answer 4

• filtration
• chromatography
• crystallisation
• simple distillation
• fractional distillation

Question 5

Plum pudding model

Answer 5

Atom is a ball of positive charge with negative electrons embedded in it

Question 6

Alpha particle scattering experiment

Answer 6

• alpha particles fired at a thin sheet of gold foil
• most particles passed through
• some particles were deflected

Question 7

Results of alpha particle experiment

Answer 7

• mass was concentrated in the middle as a nucleus
• the nucleus was positively charged
• atom was mostly empty space

Question 8

Neil Bohr

Answer 8

Suggested electrons orbit the nucleus at specific distances

Question 9

James Chadwick

Answer 9

Discovered neutrons

Question 10

Rutherford’s nuclear model

Answer 10

• small positively charged nucleus surrounded by negatively charged electrons
• mostly empty space

Question 11

Order in which the subatomic particles were discovered (first to last)

Answer 11

• electrons
• nucleus
• protons
• neutrons

Question 12

Mass of subatomic particles

Answer 12

Proton = 1
Neutron = 1
Electrons = very small

Question 13

Isotope

Answer 13

Atoms of the same element with different number of neutrons

Question 14

Early periodic table

Answer 14

Ordered in atomic weight

Question 15

Mendeleev

Answer 15

Ordered his table in order of atomic mass BUT left gaps for undiscovered elements
- He switched some elements to fit chemical properties

Question 16

Modern periodic table

Answer 16

Knowledge of isotopes made it possible to explain why the order based on atomic weights was not always correct

Question 17

Group 1 - Alkali metals

Answer 17

• one electron in their outer shell
• reactivity increases down the group
• react with water to create metal hydroxide and hydrogen

Question 18

Reaction of group 1 with water

Answer 18

Lithium -> fizzes steadily + gradually disappears

Sodium -> fizzes rapidly + melts

Potassium -> ignites with lilac flame

Gas produced is hydrogen

Question 19

Reaction of group 1 with chlorine

Answer 19

Lithium -> white powder produced

Sodium -> burns with bright yellow flame

Potassium -> more vigorous reaction than sodium

Question 20

Group 0 -> Noble gases

Answer 20

• full stable outer shell
• unreactive
• boiling points increase going down

Question 21

Transition metals

Answer 21

• strong
• high melting points and densities
• have ions with many different charges
• form coloured compounds
• good catalysts

Question 22

Explain why the reactivity increases as you go down group 1

Answer 22

• easier to lose electrons
• as there is a greater distance between outermost electron and nucleus
• so less attraction between them
• increased shielding from increased shells

Question 23

Explain why the reactivity decreases as you go down group 7

Answer 23

• harder to gain electrons
• greater distance between outermost electron and nucleus
• due to more energy shells/levels
• less attraction between (+) nucleus and (-) that is trying to be gained
• increased shielding

Question 24

Group 7 - Halogens

Answer 24

Fluorine - yellow-green gas
Chlorine - yellow-green gas
Bromine - red-brown liquid
Iodine - grey solid + purple vapour (brown in solution)
Reactivity decreases as you go down