Revision notes for C4 C5 C6, OCR 21c Triple Science

Revision notes for C4 C5 C6, OCR 21c Triple Science

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Chemistry C4 C5 C6
An element is made of only one kind of atom
Group = vertical, group number corresponds to the number of electrons in most
outer shell
Period = horizontal, corresponds to number of shells in atom
Atomic number = number of protons / electrons
RAM ­ AM = Neutrons
Nucleus is made of protons(+) and neutrons(/)
Nucleus surrounded by electrons() in shells
An atom has no overall charge
Line spectrum = light emitted from flame of an element when heated
Used to analyse unknown substances and discover new elements
Lithium ­ Red
Sodium ­ Yellow
Potassium ­ Lilac
Group 1 ­ Alkali metals
Reactivity increases as you go down group 1
Boiling / melting points decrease as you go down group 1
Group 7 ­ Halogens
Reactivity decreases as you go down group 7
Boiling / melting points increase as you go down group 7
A more reactive halogen will displace a less reactive halogen
Ions = atoms that have gained or lost electrons so have an overall charge
Ionic bonding = transfer of electrons between atoms and non metal atoms
Atom loses electrons = Positively charged ion
Atom gains electrons = Negatively charged ion
Ionic compound = compounds of Group 1 and Group 7 elements. Forms crystals as
ions are arranged in regular lattice
When crystals melt or dissolve in water they conduct electricity
Atmosphere ­ layer of gas surrounding the Earth (Nitrogen, Oxygen, Argon, Carbon
Hydrosphere ­ Mostly water and some dissolved compounds
Biosphere ­ All living things (Carbohydrates, DNA, Proteins)
Lithosphere ­ Rigid outer layer of the Earth (Aluminium, silicon, oxygen)
Electrolysis = breaking down of an electrolyte using an electric current. Used to
extract metals from their ores
Positive ions > Negative electrode
Negative ions > Positive electrode
Metals are strong, malleable, have high melting points and conduct electricity
Acids > PH less than 7
Neutral > PH 7

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Alkali > PH greater than 7
Acid + Metal hydroxide > Salt + Water
Acid + Metal oxide > Salt + Water
Acid + Metal carbonate > Salt + Water + Carbon dioxide
Acid + Metal > Salt + Hydrogen
Reactants = substances present before chemical reactions take place
Products = New substances made at the end of chemical reactions
Relative formula mass = Relative atomic mass of all elements added together
Yield = amount of product obtained from a chemical reaction
Titration ­ calculates…read more


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