Module 1

Question 1

pure substance

Answer 1

substance that is not contaminated by any other substances

Question 2

impure substance

Answer 2

one substance contaminated with small amounts of one or more other substances.
a mixture

Question 3

homogenous

Answer 3

uniform composition throughout

Question 4

heterogenous

Answer 4

having non uniform composition

Question 5

element

Answer 5

pure substance that cannot be decomposed into simpler substances

Question 6

compound

Answer 6

pure substance that can be decomposed into simpler substances,
for example into elements

Question 7

an atom

Answer 7

smallest particle of an element that is still recognisable as that element

Question 8

molecule

Answer 8

smallest particle of a substance that is capable of separating existence

Question 9

physical properties of a substance

Answer 9

characteristics that we can observe or measure without changing it into a different substance

Question 10

chemical properties of a substance

Answer 10

those associated with the chemical changes or chemical reactions the substance undergoes with it is mixed with other substances, are heated or exposed to light

Question 11

volatile

Answer 11

easily converted into a vapour or that evaporation occurs quite rapidly

Question 12

density

Answer 12

defined as mass per unit volume

Question 13

filtration

Answer 13

method of separating an undissolved solid from a liquid or solution. The solution or liquid that passes through a filter paper is called the filtrate

Question 14

distillation

Answer 14

the process in which a solution or mixture of liquids is boiled, with the vapour formed being condensed back to a liquid in a different part of the apparatus and so separated from the mixture. The liquid collected from a distillation is called a distillate.

Question 15

fractional distillation

Answer 15

process in which a mixture of liquids is separated by being put through many successive distillations (vaporisation and condensations) in one piece of equipment

Question 16

sedimentation

Answer 16

the process in which solids settle to the bottom of a container

Question 17

decanting

Answer 17

the process of carefully pouring off liquid and leaving the solid undisturbed at the bottom of the container

Question 18

two liquids are immiscible if

Answer 18

when they are mixed, they do not for a homogenous liquid

Question 19

miscible

Answer 19

liquids that mix to form a homogenous liquid

Question 20

metals are elements that

Answer 20

solids at room temperature
shiny or lustrous appearance
good conductors of heat and electricity
malleable and ductile
high bp and mp
dense

Question 21

structure of atom

Answer 21

extremely small dense nucleus/core which contains the bulk of the mass of the atom and carries positive electrical charges.
nucleus is surrounded by an electron cloud of rapidly moving and extremely light negatively charged particles

Question 22

isotopes

Answer 22

atoms of the one element that have different numbers of neutrons in their nuclei (although the same number of protons)

Question 23

chemical properties and physical properties of isotope

Answer 23

Isotope of the one element have the same chemical properties and very similar
physical ones

Question 24

radioactive isotopes

Answer 24

spontaneously emit radiation. They are also
called unstable isotopes

Question 25

what are the 3 radiations emitted from radioisotopes

Answer 25

Alpha rays (α) which are helium nuclei Beta rays (β) which are electrons Gamma rays (γ) which are a type of electromagnetic radiation like light and x-rays

Question 26

nucleur equation

Answer 26

shows the disintegration of a radioisotope

Question 27

what is first, second, third energy level

Answer 27

electrons in an atom exist in discrete energy levels through electron configuration energy shells/energy levels

Question 28

what are valence electrons in terms of energy level/energy shells

Answer 28

highest energy level (outermost energy shell)

Question 29

orbital

Answer 29

volume of space surrounding the nucleus of an atom through which one or two electrons may randomly move

Question 30

what the orbitals called

Answer 30

each main energy level is made up of energy sublevels called spdf sublevels

Question 31

orbital notation

Answer 31

in terms of shells and subshells, 1s

Question 32

why do electrons get excited

Answer 32

An electron in an atom can be given extra energy and so be raised from its ground state into an excited state fall back into their ground states, energy is released in the form of ultraviolet, visible and infrared radiation, photons of light creates a pattern of lines called emission spectrum

Question 33

the bohr theory

Answer 33

electrons as particles orbiting the nucleus as planets orbit the sun

Question 34

schrodinger's theory

Answer 34

electrons move at extremely high speeds randomly throughout volumes of space around the nucleus called orbitals

Question 35

periodicity

Answer 35

regular recurrence of events or properties

Question 36

atomic radius trends

Answer 36

decreases along the period - attraction between electrons in shells and protons in nucleus pulls shells closer to nucleus increases down a group- increase in shells

Question 37

first ionisation energy

Answer 37

the energy required to remove an electron from an atom

Question 38

equation for ionisation energy

Answer 38

M(g) → M+(g) +e-

Question 39

trends of first ionisation energy on periodic table

Answer 39

increases across period: as attraction between valence electrons and nucleus increases, radius gets smaller and harder to remove valence electrons decreases down group: more shells means less attraction of valence electrons to nucleus, making ti easier to remove outmost electrons

Question 40

electronegativity of an element

Answer 40

a measure of the ability of an atom of that element to attract bonding electrons towards itself in compounds. the higher the electronegativity the stronger the attraction for bonding electrons

Question 41

trends of electronegativity on periodic table

Answer 41

increases across period: change from metal to non metal... decreases down group: increase in metallic character...

Question 42

state if the following are compressible/incompressible and how they fit ina container solids liquids gases

Answer 42

solids: incompressible and holds its shape liquids: incompressible and fills the shape of the container gases: compressible and fills the shape of the container

Question 43

examples of physical properties

Answer 43

appearance, colour, magnetism, mp, bp, density, malleability, ductility, solubility in water

Question 44

examples of chemical properties

Answer 44

rate of reactivity to water, acids, and substances, oxygen, rate burnt by oxygen, if its acidic or basic

Question 45

separation techniques based on bp

Answer 45

evaporation, distillation, fractional distillation

Question 46

separation techniques based on density

Answer 46

decanting, seperating funnel, centrifuging

Question 47

separation techniques based on particle size

Answer 47

sieving, filtration

Question 48

reason for each radioactive type of decay

Answer 48

alpha: nuclei have too few neutrons to be stable beta; nuclei has too many neutrons to be stable gamma: unstable atom releasing energy

Question 49

why is carbon 12 important

Answer 49

its used as the standard from which atomic masses of all nuclides are measured

Question 50

what are shells also called

Answer 50

energy levels

Question 51

what group numbers are each subshell

Answer 51

s: Group 1-2 p: group 13-18 d: group 3-12 f: lanthanides and actinides

Question 52

What does bonding depend on?

Answer 52

The difference in electronegativity If big: electron will be transferred and make an ionic compound If small: electrons will be shared and make a covalent compound

Question 53

Do metals comonnly lose or gain electrons

Answer 53

They lose since most charges are +1 to +3

Question 54

the metallic bonding model

Answer 54

describes metals as a metallic structure which consists of a regular arrangement of stable, positively charged metal ions, called cations, surrounded by a 'sea' of freely moving delocalised valence electrons. The metal atoms achieve stability by releasing their valence electrons to become the surrounding 'sea'.

Question 55

metallic bonds

Answer 55

electrostatic attraction between the cations and the freely moving electrons

Question 56

characteristics of ionic compounds

Answer 56

brittle, hard (resistant to scratching, high mp, cant conduct electricity in solid state but can in liquid or aqueous state

Question 57

ionic bonding model

Answer 57

ionic networks that consists of a regular arrangement of metal cations and negativitely charged non-metal ions called anions electronegativity difference is high

Question 58

ionic bonds

Answer 58

electrostatic attractions between the oppositely charged ions

Question 59

electrovalency

Answer 59

charge of an ion

Question 60

what type of ion is metals

Answer 60

cations

Question 61

what type of ion is non-metals

Answer 61

anion

Question 62

why do covalent bonds share electrons

Answer 62

since non metals have similar electronegativity and therefore result to share electrons

Question 63

why do ionic bonds transfer electrons

Answer 63

since metals and non metals have a big difference in electronegativity and therefore attract each others electrons.

Question 64

discrete molecules

Answer 64

formed containing fixed numbers of atoms. diatomic molecules

Question 65

intramolecular forces

Answer 65

forces that hold atoms together within a molecule

Question 66

intermolecular forces

Answer 66

forces that exist between molecules

Question 67

molecular shapes

Answer 67

linear, bent, trigonal planar, tetrahedral, pyramidal

Question 68

properties of covalent molecular substances

Answer 68

low mp and bp: weak intermolecular forces (substnce must be cooled to form fixed lattice) non-conduction fo electrcity in solid or molten states: no free moving particles softness

Question 69

covalent network

Answer 69

a three dimensional network of atoms fixed in place, held together by strong covalent bonds extending through lattice covalent network structure: forms when covalent bonds extend throughout an entire substance (diamond) covalent layer network: forms when covalent bonds extend throughout layer in a substance, weak dispersion forces between layers (graphite)

Question 70

explanation for properties of metallic substances

Answer 70

good conductors of heat and electricity: delocalised electrons transfer charge and thermal energy high mp and bp: strong metallic bonding extending throughout the lattice dense: ions tightly packed in the lattice malleable and ductile: distortions does not distrupt the metallic bonding lustrous: delocalised electrons cause reflection of light

Question 71

explanation of properties of ionic substances

Answer 71

non conductors of electricity when solid: ions firmly bound in the lattice, so no moving charged particles conductors when molten or aqueous: ions free to move high mp and bp: strong ionic bonding extending throughout the lattice hard: ions strongly bound in the lattice brittle: distortion causes repulsion between ions of like charge

Question 72

explanation of properties of covalent molecular substances

Answer 72

non conductors of electricity unless reacted with water to produce ions: molecules are uncharged and electrons are localised in covalent bonds or on the atoms low mp and bp: weak forces between molecules soft solids, liquids or gases: weak forces between molecules

Question 73

explanation of properties of covalent network substances

Answer 73

non conducters when solid or molten: electrons localised in covalent bonds or on the atoms very high mp: atoms strongly bound in the lattice hard: strong covalent bonding extending throughout the lattice brittle: distortion breaks covalent bonds

Question 74

form a flow chart of different bonds

Answer 74

see in onenote

Question 75

covalent molecular compounds

Answer 75

neutral molecules held together by weak intermolecular forces strong covalent bonds within molecule but forces between molecules are weak

Question 76

why is graphite an excluded example of a covalent network bond?

Answer 76

is has layers of covalent bonds that have weak intermolecular bonds but strong intramolecular bonds they can conduct electricity since there are extra electrons forming clouds between the layers,

Question 77

what are the two types of pairs in VSEPR

Answer 77

bonding pairs: between two atoms lone pairs: not involved in bonding

Question 78

what is the VSEPR theory

Answer 78

valence shell electron pair repulsion

Question 79

why do lone pairs take up more space

Answer 79

lone pair electrons repel each other more than bonding pairs

Question 80

what is diamond

Answer 80

a carbon covalent network each carbon atom is covalently bonded to four other carbon atoms in a tetrahedral arrangement hard, high mp, not conductor of electricity,

Question 81

what is silicon dioxide

Answer 81

a covalent network each Si atom joined to 4 oxygen atoms main substance in rocks, when pure: quartz

Question 82

trends of state of matter at room temperature

Answer 82

melting points increase across periods 1-3 from groups 1-14 then drastically drop for groups 15-18