Chemistry Revision All Flashcards
(112 cards)
1
Q
Define the ‘periodic table’
A
Classification of the elements based from comparing their physical and chemical properties
2
Q
What is in atomic mass?
A
Number of protons and neutrons combined
3
Q
How do you find out the number of neutrons in an atom?
A
Atomic mass - atomic number (protons) = neutrons in atom
4
Q
What is the row in the periodic table called (horizontal) and what can you find out about it?
A
Periods, number of electron shells in the number of the period
5
Q
What are the columns called in the periodic table? What can you find out about it?
A
Groups, it is number of electrons in the outer (valence) shell
6
Q
Define ‘valent electron/valence shell?
A
Number of electrons in the outermost shell
7
Q
Define ‘element’
A
Pure substances, cant be broken down further by chemical/physical means, made up by only 1 type of atom
8
Q
Define ‘atom’
A
Smallest particle of chemical element that exists (buildings blocks of all matter)
9
Q
Why are atoms in groups 8 and 4 not reactive?
A
4 - Hard to gain or lose 4 whole electrons, so hard to bond to become stable
8 - Already full, no point in losing/gaining electrons
10
Q
Define ‘Ions’
A
If an atom loses/gains electron to become stable, gains/loses electrons so has a charge
11
Q
Define ‘Anion’
A
When an atom gains electrons (negative charge) as more electrons compared to protons
12
Q
Define ‘Cation’
A
When atom loses electrons (positive charge atom) as more protons than electrons (less electrons than protons)
13
Q
Define an ‘Isotope’
A
When single element/same element has a different number of neutrons than it’s original form on periodic table (same number of protons but different number of neutrons)
14
Q
What is the rule that states electrons in a re shell are ordered (2,8,8,8…)
A
Octet rule
15
Q
Describe the subatomic particle ‘electron’
A
Symbol = e
Charge = -ve
Atomic mass = 0.0055
16
Q
Describe the subatomic particle ‘proton’
A
Symbol = p
Charge = +ve
Atomic mass = 1
17
Q
Describe the subatomic particle ‘neutron’
A
Symbol = n
Charge = neutral/no charge
Atomic mass = 1
18
Q
What is a full key for a Bohr diagram
A
Key
p = proton (+ve) –> nucleas
n = neutron (neutral/no charge) –> nucleas
dot = electron (-ve) –> electron shell
19
Q
Predict the charge of a ‘group 1’ atom if it were to bond?
A
1+, as it will lose 1 electron (1 less electron than proton)
20
Q
Predict the charge of a ‘group 2’ atom if it were to bond?
A
2+, as it will lose 2 electron (1 less electron than proton)
21
Q
Predict the charge of a ‘group 3’ atom if it were to bond?
A
3+, as it will lose 3 electron (3 less electron than proton)
22
Q
Predict the charge of a ‘group 4’ atom if it were to bond?
A
It needs to gain or lose 4 electrons to become stable (too much energy needed to bond)
23
Q
Predict the charge of a ‘group 5’ atom if it were to bond?
A
3-, as it will gain 3 electron (3 more electron than proton)
24
Q
Predict the charge of a ‘group 6’ atom if it were to bond?
A
2-, as it will gain 2 electron (2 more electron than proton)
25
Predict the charge of a 'group 7' atom if it were to bond?
1-, as it will gain 1 electron (1 more electron than proton)
26
Predict the charge of a 'group 8' atom if it were to bond?
Nothing, because it is already stable and has either 2 or 8 electrons in its outermost shell
27
Define 'Inert'
Does not react
28
What is the chemical formula for 'Methane'?
CH₄
29
What is the chemical formula for 'Ammonia'?
NH₃
30
What is the chemical formula for 'Ammonium'?
NH₄⁺
31
Define 'Compound'
Pure substances chemically bonded together (only separated through chemical means, not physically)
Composed of 2/more different elements joined by chemical bonds
32
Define 'Mixtures'
2 or more substances mixed together (physically)
No chemical change takes place
Separated physically
33
What is special about group 7?
Halogens
34
What is special about group 8?
Noble gases (stable)
35
What is special about group 1?
Alkaline Metals
36
What is special about group 2?
Alkaline Earth Metals
37
What are examples of mixtures?
Air, sea water, most rocks
38
What are examples of compounds?
Water
Carbon dioxide
Magnesium oxide
Sodium chloride
39
How can compounds be separated?
Chemical reactions, chemical means
40
How can mixtures be separated?
Easily, physically
41
What is the property of a mixture?
Each substance is easily separated from the mixture
42
What is the property of a compound?
The properties are different to the elements it contains
43
What is the composition of a mixture?
You can vary amount of each substance in a mixture
44
What is the composition of a compound?
It has 'definite composition'
Cannot vary amount of each element
45
Define 'Chemistry'
Study of the composition, structure and properties of matter and the changes it undergoes
46
Define 'Alloy'
A metal made by combining two/more metallic elements together, to give it greater strength (not pure)
47
What is in a chemical equation?
Reactants --> products
48
What is plasma?
High temperature, ionized phase of matter as found on the sun
49
What are all physical properties for elements?
Melting points, boiling points, density, colour, hardness, texture
50
What are all chemical properties for elements?
Flammability, reactivity
51
What are three categories of elements?
Metals, non-metal, mettaloids
52
What are properties of metals?
Shiny, conductors of heat/electricity, malleable, ductile
53
What are properties of non-metals?
Dull, non-conductors, non-malleable, brittle
54
What are properties of metalloids?
Semiconductors, characterisations of both metals and non-metals
55
What 2 things are in a solution?
Solvent, Solute
56
What is a solvent?
Thing that does the dissolving in a solution
57
What is a solute?
Thing that gets dissolved in the solution
58
What are solutions?
A mixture that appears to be a single substance E.G: (salt in water, air in oxygen, nitrogen and oxygen)
59
Define 'concentrated'?
Means that theres lots of a substance in a solution (intense)
60
Define 'dilute'?
Not concentrated, make a liquid weaker by adding water/another solvent to it
61
Define 'colloid'?
Mixture in which particles are dispersed throughout, but no heavy enough to settle (milk, jelly, muddy water)
62
Define 'suspension'?
Mixture in which particles of solid material arent dissolved, but suspended in the mixture somewhat evenly throughout the liquid/gas, large enough that they settle out and form sediment eventually (snow globe)
63
Define 'Radiation'
Emission of energy through rays/waves or subatomic particles
64
Define 'Contamination'
Radioactive material spilled someplace you don't want it in
65
Define 'Chemical equation'
Representation of chemical reaction through symbols of elements to indicate amount of substance in reactants and products
66
Define 'Chemical reaction'
Process that involves rearrangement of molecular or ionic structure of substance or compound
67
Define 'Ionising radiation'
When radiation collides with atoms/molecules and alters their molecular structure by knocking of electrons, leaving behind ions
68
How is gamma, beta and alpha rays/particles stopped?
Alpha -> skin/piece of paper
Beta -> thin piece of aluminium
Gamma -> Thick piece of lead
69
How fast are all three particles/radiaiton?
Alpha --> 10% speed of light
Beta --> 90% speed of light
Gamma --> speed of light
70
What is the mass of all three radiation?
Alpha --> 4 AMU as 2 protons/nucleas
Beta --> 0.055 AMU or really low (1 electron)
Gamma --> No mass as high frequency electromagnetic wave
71
What is ionising ability of three radiations?
Alpha --> 20 electrons per 'a' particle
Beta --> 1 electron per 'B' particle
Gamma --> 1 electron per 'y' ray
72
What occurs during alpha decay?
Nucleas ejects alpha particle (2 protons, 2 neutrons)
Loses 4 atomic mass
Loses 2 atomic number
73
In which atoms do alpah decay occur?
Mass number greater than 100 or heavy nuclei
74
How dangerous is alpha radiation/radioisotopes emitting alpha radiation?
If gets inside body, fatal
If outside body it can only travel few cm in air, cant penetrate skin so not dangerous, has potential
75
How ionizing are all radiations?
Alpha - very as large, heavy, slow and large charge so large attraction to alpha particle (2+)
Beta - Medium power as only 1 electron and can only ionize 1 electron, low charge (close to electron)
Gamma - really low as no charge as it is a high frequency electromagnetic wave (needs direct contact)
76
What occurs in beta decay?
Neutron converted into proton, and loses 1 electron
Increases atomic number by 1 (creating new element)
77
How dangerous is beta particle?
Likely to cause radiation burns to skin/eyes as small/fast and CAN PENETRATE SKIN more deeply than alpha
78
When does gamma decay occur?
When proton/neutrons rearrange inside nucleus and don't emit any particles (instead gamma ray) as lots of energy and emits light (gamma ray)
79
Define 'Transmutation'
Process of atom converting to another element, cant happen through chemical reaction as instead through nuclear decay of the 3
80
Why chemical reactions cant transmutate?
Chemical reactions involve electrons (ions), while nuclear decay changes in nucleas to change to new element
81
Define 'Nuclear decay'
Type of nuclear reaction which can cause atoms to change elements
82
What occurs and what is radioisotope?
Tiny fraction of atoms have unstable nuclei (radioisotopes) and thus undergo nuclear decay at any time and transmutate after decaying to become more stable and radioactive
83
Define 'Half life'
Time takes for half of the nuclei to decay (less than second - millions of years)
84
Define 'Nuclear radiation'
Any rays/particles emitted/released by nuclei (alpha, beta, gamma)
Harmful to living organsims
85
Describe ALL features of covalent bonding
Between non-metals (close periodic table) both want gain to become full
Sharing electrons
Both nuclei equal hold over shared electrons
Can create diatomic gases/elements H2, O2 etc
86
What are all prefixes for covalent naming?
```
Mono
Di
Tri
Tetra
Penta
Hexa
Hepta
Octa
Nona
Deca
```
87
What are ALL properties of covalent bonding?
No charges and can't conduct electricity
Often liquids/gases
Low solubility
Geometrical shaped molecules
88
Describe ALL features of Ionic Bonding?
Between metals and non -metals
Metals lose electrons to become stable and cation
Non-metals gain electrons from metals to become stable and anion
Form electrostatic attraction form 1 positive, 1 negative ion (oppositely charged ions)
89
What are ALL properties of Ionic Bonding?
Form crystal lattice structures as (cations attracted to anions and stack up to stable structure)
Soluble in water, partials charges in water disperse anions and cations in ionic compound
High melting points as large amount of energy needed to separate attraction
Conduct electricity in water (electrons free to move between ions)
90
What are polyatomic ions?
Compound with more than 1 atom
Are non-metals covalently bonded
Entire compound has a charge and can bond ionically AS A GROUP
91
```
What are all polyatomic ions?
OH1-
NO3 1-
CO3 2-
SO4 2-
PO4 3-
```
```
Hyrdoxide
Nitrate
Carbonate
Sulfate
Phosphate
```
92
What is 'Metallic bonding'?
When multiple metal positive ions are attracted in lattice structure delocalise their valence electrons to form 'sea of electrons'
Electrons move around each atom, acting as glue and keeping lattice structure strong
Good heat/electricity conductors due to moving electrons
93
What 5 things are evident in a chemical change?
```
Release of energy as heat
Release of energy as light
Change in colour
Formation of gas
Change in odour
```
94
What are all 6 types of chemical reactions?
```
Neutralization
Combustion
Synthesis/formation
Decomposition
Single displacement
Double displacement
```
95
Describe neutralization
When acid (H donor) and base (OH / H acceptor) react together to neutralise their acidity/base to become more neutral and form salt + water
Acid + Base --> Salt + Water
96
Describe combustion
AB + O2 --> CO2 + Water
Compound reacts with oxygen to form fire (exothermic), with carbon dioxide and water
97
Describe synthesis
A + B --> AB
2/more reactants join to form compound
98
Describe decomposition
AB --> A + B
Compounds like ionic/covalent decompose to produce simple 2/more elements/products
99
Describe single displacement
A + BC --> AC + B
Replace/swap one element with an element in a compound
100
Describe double displacement
AB + CD --> AD + CB
Second element from both compounds swap/replace
Form 2 new compounds
101
Describe 'Exothermic'
Reaction RELEASES ENERGY as reactants have more energy than products, and need to release to make equal
Releases as heat/light (like fire/combustion as both)
102
Describe 'Endothermic'
Reaction absorbs heat (from surroundings) --> making them feel colder
Because products have more energy than reactants and need more energy to fulfill reaction
103
What is incomplete combustion?
When combustion has limited oxygen to do reaction, being incomplete as and creating 'dirty carbon' as soot/smoke/charcoal/carbon monoxide (poisonous gas)
104
What are the 3 acids and 1 base to memorise?
Sulfuric acid --> H₂SO₄
Hydrochloric acid --> HCL
Nitric acid --> HNO₃
Sodium hydroxide --> NaOH
105
What are the three acid reactions?
Acid + Base --> Salt + Water
Acid + Metal --> Salt + H₂ (Hydrogen gas)
Acid + Carbonate --> Salt + Water + Carbon Dioxide (CO₂)
106
What is an acid?
Common, dangerous, can cause burns to skin, some are safe to eat/drink
Stomach acids help digest food
```
Taste sour
Affect indicators (blue litmus --> red) (Methyl orange turns red)
```
Proton donors --> Donate H+ ions
Strong acid has lots of H+ and weak has little
pH 6 or lower
107
How do you test for hydrogen gas?
Use lit splint, if pops it is H₂
108
How do you test for Carbon Dioxide (CO₂)?
Use lit split, if fire goes it, it is carbon
When put carbon dioxide into limewater (Ca(OH)₂), creates a precipitate of calcium carbonate (CaCO3)
CO₂ + Ca(OH)₂ --> CaCO3
109
How do you test for oxygen?
Should relight a glowing splint because oxygen needed for combustion
110
What is a base?
Taste bitter
Red litmus turns blue
Phenolphthalein turns purple
H+ acceptors
pH 8 or higher
Examples --> NA
111
What is an indicator?
Substance that changes colour in the presence of a base/acid
Can detect it using an indicator
Blue litmus --> red with acid
Red litmus --> blue with base
112
What are all types of indicators?
Universal Indicator
Methyl Blue
Phenolphthalein
