Core Chemistry

GCSE core science AQA chemistry

HideShow resource information
Preview of Core Chemistry

First 305 words of the document:

All substances are made of atoms. A substance that is made of only one sort of atom is called an element; there are about 100 different elements- elements are
shown in the periodic table; e.g. H, N, O, F, Br, I. The vertical columns are called groups and contain elements with similar properties
Atoms have a small central nucleus which is made of protons and neutrons around it there are electrons:
An atom is the smallest part of an element that can exist on its own. A compound contains atoms of two or more elements bounded together
The relative electrical charges and masses of subatomic particles are:
Name of Charg Mass
particle e
Proton +1 1
Neutron 0 1
Electron -1 Very small
In an atom the number of electrons is equal to the number of protons in the nucleus. Atoms have no overall electrical charge. All atoms of a particular element have the
same number of protons; atoms of different elements have a different number of protons.
Atoms are arranged in the periodic table in order of their atomic number
Atomic number is the number of protons in an atom (proton number)
Mass number is the sum of the protons and neutrons in an atom (bigger number)
C1 1.3: The arrangement of electrons in atoms
The electrons move around the nucleus in energy levels (or shells)
The electrons occupy the lowest available energy level (innermost, closest to the nucleus)
Elements in the same group in the periodic table have the same number of electrons in the outermost shell giving them similar chemical properties
The first shell can hold up to 2 electrons; the second shell can hold up to 8 electrons; and the third shell can hold up to 8 electrons

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

Potassium has atomic number 19, so 19 electrons; its electron structure is 2,8,8,1
The elements in Group 0 of the periodic table are called the noble gases; they're uncreative because their atoms have similar chemical properties.
Ionic bonding Covalent bonding
Transfer electrons to form ions Share electrons to form molecules
between metal and non-metal; the between non-metals
attraction between oppositely Covalent bond examples: chlorine,
charged particles hydrogen chloride, water, ammonia,
methane, oxygen and hydrogen.…read more

Page 3

Preview of page 3

Here's a taster:

Calcium carbonate Calcium oxide + Carbon dioxide
(Limestone) (Quicklime) + Carbon dioxide
Limestone and its products have many uses, e.g. to make slaked lime, mortar, cement, concrete and glass.
Most metal carbonates undergo thermal decomposition to form metal oxide and carbon dioxide; the general equation for thermal decomposition is:
Metal carbonate metal oxide + carbon dioxide
Some carbonates are stable and don't break down on heating, e.g. Group 1 carbonates.…read more

Page 4

Preview of page 4

Here's a taster:

Carbonates react with acids to produce carbon dioxide, a salt and water- this is how limestone is damaged by acid rain: CaCO + 2HCl CaCl +HO +CO
Limewater us used as a test for carbon dioxide, it turns clear limewater murky
Limewater + carbon dioxide carbon carbonate + water
Ca (OH) + CO CaCO + HO
Quicklime is made by heating limestone:
Limestone + Quicklime Carbon dioxide
Calcium carbonate + Calcium carbonate Fizzy gas
Quicklime reacts with water…read more

Page 5

Preview of page 5

Here's a taster:

Cement: Limestone and clay are heated together; it can be set in wet conditions
Concrete: Limestone and clay are heated, then mixed with aggregate (small stones and crushed rocks)
C1 2.…read more

Page 6

Preview of page 6

Here's a taster:

C1 3.1 Extracting metals
Reactivity series (list of metals); the method of extraction depends on the metal's position in the reactivity series:
Ores are naturally occurring rocks in the Earth's crust which contain metal compounds in sufficient amounts to make it worthwhile extracting them; un-reactive metals
(e.g.…read more

Page 7

Preview of page 7

Here's a taster:

Copper oxide + Carbon Copper + Carbon dioxide
2CuO + C 2Cu + CO
Oxidation Is Loss of oxygen, Reduction Is Gain of oxygen [OILRIG]
Metals that are more reactive than carbon (e.g. aluminium) are extracted by electrolysis of molten compounds. The use of large amounts of energy in the extraction of
these metals makes them expensive.…read more

Page 8

Preview of page 8

Here's a taster:

Types of
Properties Uses
Carbon steel Low carbon Soft, malleable Cars
High carbon Strong, but brittle Ships
Low alloy steel Nickel Resistant to stretching
Tungsten Works at high temperatures Furnaces
Stainless steel Cr- Ni Corrosion resistant Cutlery
Aluminium and titanium
Metal Uses Properties Method of extraction
Aluminium Aeroplane, drink Strong, light By using electrolysis as
cans, racing bikes, (density), high it's very reactive
saucepans melting point,
resistant to
corrosion as it
forms an oxide
Titanium Cans, hip By displacement of…read more

Page 9

Preview of page 9

Here's a taster:

Extracting copper from its ore
Add sulphuric acid to copper ore to Heat copper ore very strongly in a
form copper sulphate solution. The furnace (smelting) to produce crude
crude oil can be purified by electrolysis copper which can be purified by
or by displacement using scrap iron. electrolysis, for example heat copper
Copper sulphate + iron copper + sulphate with air.…read more

Page 10

Preview of page 10

Here's a taster:

Hard, tough, strong Cars, trains
Malleable (can be bent or hammered into shape) In buildings: construction
Ductile (can be drawn out into wires)
High melting point (except mercury which is a liquid)
Copper, gold and aluminium are all alloyed with
other metals to make them stronger
C1 3.…read more


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all resources »