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Chemistry
UNIT 1 ATOMS, BONDS AND GROUPS (F321)
Atoms
Isotopes = atoms of the same element with different numbers of neutrons
Relative isotopic mass = mass of an atom of an isotope compared with onetwelfth of the mass
of an atom of carbon12
Relative atomic mass = weighted mean mass…

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Ethanoic (acetic) acid > CH3COOH
Methanoic (formic) acid > HCOOH
Citric acid > C6H8O7

Acid is a proton donor (releases H+ ions)

Bases
Metal oxides and hydroxides (e.g. CuO and Mg (OH)2 )
Ammonia and amines (e.g. NH3 and CH3NH2)

Base is proton acceptor

Alkali > type of base that…

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uncombined element: 0
combined oxygen: 2
combined hydrogen: +1
combined fluorine: 1
simple ion: charge on the ion

overall charge on molecule is zero, sum of oxidation numbers must equal overall charge
sometimes the oxidation number included in the name of the compound/ion as Roman numeral

Redox reactions
oxidation =…

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Ionic bonding
Ionic bonding = electrostatic attraction between oppositely charged ions

DOT AND CROSS DIAGRAMS

Group 1,2,3 have positive charge same as group number
Group 4 usually no charge
Group 5,6,7 have negative charge

NO3 , CO3 2, SO4 2, NH4 +

properties
soluble in POLAR solvents (e.g. H2O)

Covalent…

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Electronegativity
Electronegativity is measure of attraction of bonded atom for pair of electrons in covalent bond

more electronegative atom (greater attraction) takes negative charge electronegativity
increases to the right of P.T.

permanent dipole

To predict type of bonding greater difference between electronegativities of bonding, greater
ionic character, greater similarity, greater…

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reactivity increases down a group, increasing ease of losing electrons
first ionisation energies decrease

react with oxygen redox reaction, product = ionic oxide (MO)

react with water, product = hydroxide (M(OH)2) and hydrogen gas

Reactions
MO and M(OH)2 both react with acids to form a salt and water
Observe >…

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ability to gain an electron into the p subshell decreases

more reactive halogen will oxidise + displace halide of a lessreactive halogen (displacement)

Form solutions with different colours

Chlorine oxidises Br and I ions:
Cl2 (aq) + 2Br (aq) > 2Cl (aq) + Br2 (aq) orange in water, orange in…

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