C3 Atoms, elements and compounds

Question 1

define an element (1)

Answer 1

made of one type of atom

Question 2

define a compound (1)

Answer 2

made of more than one type of atom chemically bonded together

Question 3

define a mixture (1)

Answer 3

two of more elements / compounds mixed together that can be separated by physical means

Question 4

describe a properties of metals (7)

Answer 4

• usually solid in room temperature
• malleable
• ductile
• shiny
• high melting and boiling point
• high density
• good thermal and electrical conductivity

Question 5

what is the difference between a physical change and chemical change (2)

Answer 5

physical changes involve a change in state / separation of a mixture.
chemical changes involve at least one new substance being made

Question 6

what is the difference between color between the anhydrous and hydrated form of copper (II) sulfate (2)

Answer 6

anhydrous - white
hydrous - blue

Question 7

what is the differences between color between the anhydrous and hydrated form of cobalt (II) chloride (2)

Answer 7

anhydrous - blue
hydrous - pink

Question 8

describe the structure of an atom (2)

Answer 8

central nucleus containing protons and neutrons
shell of electrons

Question 9

describe the relative charge and mass of protons (2)

Answer 9

relative charge –> +1
mass –>1

Question 10

describe the relative charge and mass of neutrons (2)

Answer 10

relative charge –> 0
mass –> 1

Question 11

describe the relative charge and mass of electrons (2)

Answer 11

relative charge –> -1
mass –> 1/2000

Question 12

describe the maximum number of electrons that can fit on the first 3 shells (1)

Answer 12

1st - 1
2nd - 8
3rd - 8

Question 13

why are the elements in group 0 (noble gases group 8) unreactive (1)

Answer 13

they have a full outer shell of electrons

Question 14

how is group number in the periodic table related to electronic structure (1)

Answer 14

group number = number of electrons in the outer shell

Question 15

how is periodic (row) number in the periodic table related to electronic structure

Answer 15

row number = the number of occupied electron shells

Question 16

what is the atomic (proton) number of an element (1)

Answer 16

number of protons in an atom

Question 17

what is the mass (nucleon) number of an element (1)

Answer 17

number of protons and neutrons in an atom

Question 18

how are elements arranged in the periodic table (1)

Answer 18

in ascending atomic number, elements with similar properties arranged in groups

Question 19

define an isotope (2)

Answer 19

atoms of the same element with the same number of protons and electrons but a different number of neutrons

Question 20

why do isotopes have the same chemical properties (2)

Answer 20

bc they have the same number of electrons in their outer shell

Question 21

describe how metal atoms form ions (2)

Answer 21

metals lose electrons to form positive ions

Question 22

describe how nonmetals atoms form ions (2)

Answer 22

nonmentals gain electrons to form negative ions

Question 23

describe an ionic bond (2)

Answer 23

the electrostatic attraction between positive metal ions and negative non metal ions

Question 24

what type of structure do ionic substances form (1)

Answer 24

giant ionic lattice

Question 25

explain the high melting / boiling point of ionic substances (2)

Answer 25

high melting point due to strong electrostatic force of attraction between ions that requires a lot of energy to overcome

Question 26

describe the properties of ionic substances (4)

Answer 26

- low volatility - high solubility - high melting and boiling point - conducts electricity when molten or aqueous

Question 27

explain the electrical conductivity of ionic substances (2)

Answer 27

able to conduct when molten of aqueous bc the ions are free to move and carry charge (not electrons)

Question 28

describe a covalent bond (1)

Answer 28

a shared pair of electrons between non metal atoms

Question 29

describe the properties of covalent substances (4)

Answer 29

- high volatility - low solubility - low melting and boiling point - does not conduct electricity

Question 30

explain low melting / boiling point of covalent substances (2)

Answer 30

weak intermolecular forces that require a small amount of energy to overcome

Question 31

explain why simple covalent substances don't conduct electricity (2)

Answer 31

no free mobile charge carriers (electrons or ions) to carry charge through the structure

Question 32

name 3 macromolecules (3)

Answer 32

- diamond - graphite - silicon(IV) oxide

Question 33

describe the structure of diamond (3)

Answer 33

- giant structure - made of carbon atoms - each carbon forms 4 bonds with another carbon

Question 34

describe the structure of graphite (4)

Answer 34

- giant structure - made of carbon atoms - each carbon forms 3 bonds with another carbon - layered structure

Question 35

describe the structure of silicon (IV) oxide (2)

Answer 35

- giant structure - one silicon atom for every two oxygen atoms

Question 36

explain why diamond, graphite and silicon oxide have a high melting / boiling point (2)

Answer 36

lots of strong covalent bonds that require a lot of energy to overcome

Question 37

explain why graphite is able to conduct electricity (3)

Answer 37

carbon atoms only form 3 bonds so one valence electron is free and delocalised and can carry charge through the structure

Question 38

explain why graphite is slippery (2)

Answer 38

weak intermolecular forces between layers so the layers can slide off each other

Question 39

what is graphite used for (2)

Answer 39

- lubricant - conductor

Question 40

what is diamond used for (2)

Answer 40

- cutting tools - jewelry