A. Definitions Flashcards
Simple Ion
Atom which has lost or gained electrons
isomer
Same molecular formula Different structural formula
Hydrocarbon
Compound containing only C and H atoms
Acid
Solution containing a higher number of H+ (aq) ions than OH- (aq) ions
Molecule
2 or more atoms joined together by covalent bonds
Covalent bond
A shared pair of electrons
Isotope
Atoms with
Same atomic number Different mass number
Alkali
Solution with higher numbers of OH- (aq) ions than H+ (aq) ions
Atomic number
Number of protons in an atom
Fuel
A substance that burns to release energy
Combustion
Combining with oxygen to release energy
Valency
The number of unpaired outer electrons in an atom
Element
Substance containing only one type of atom
Mass number
The sum of the number of protons and neutrons in an element
Solute
A substance that will dissolve in a liquid (water)
Diatomic
A molecule containing two atoms
What are the 7 diatomic elements?
- Iodine
- Hydrogen
- Nitrogen
- Bromine
- Oxygen
- Chlorine
- Fluorine
Exothermic
A reaction that releases energy to the surroundings
Endothermic
Reaction in which heat energy is taken in from the surroundings
What are the properties of protons?
Charge : 1+
Mass: 1 a.m.u
Found: in the nucleus
What are the properties of neutrons?
Charge: 0
Mass: 1 a.m.u
Found: in the nucleus
What are the properties of electrons?
- Charge: 1-
- Mass: 0
- Found : in shells around nucleus
Period
Horizontal row of elements in the periodic table

Electricity
The flow of charged particles
(electrons and ions)
Solvent
A liquid into which a substance will dissolve
Homologous series
Compounds with
Same general formula AND Similar chemical properties
(both needed)
Lattice
A regular, repeating 3-D structure
( ionic and metallic)
Saturated
A substance where all C to C bonds are single
Unsaturated
A substance contains (at least) one C=C bond
Halogen
Any of the group 7 elements
Alkali metal
Any of the group 1 metals
They form alkalis when reacting with water
Salt
When the H+ aqueous ions of an acid are replaced by metal (or ammonium) ions
- sulphuric acid gives sulphate salts
- hydrochloric acid gives chloride salts
- nitric acid gives nitrate salts
What is meant by Neutralisation of acids
Removing excess H+ (aq) ions from a solution
What is a Base?
A substance that neutralises an acid
What are the 3 types of base?
- Metal Hydroxide
- Metal Carbonate
- Metal Oxide
What is meant by Pollution?
The introduction of harmful substances into the environment
Spectator ion
An ion that doesn’t take part in a reaction
Reactions of acids Displacement reactions
Catalyst
A substance that increases the rate of a reaction
Indicator
A substance that changes colour when something is added to it
Solution
A mixture of a solvent and a solute
Electrolysis
Breaking apart an ionic compound using electricity
Noble gases
Unreactive group 8 elements
Ion migration
Movement of ions to opposite charged terminal
A mole
The gram formula mass of a substance
Relative atomic mass (RAM)
The average mass of an element taking into account the relative abundance of each isotope
Density
Mass divided by volume
Electrostatic attraction
Attraction between oppositely charged particles
Acid rain
Rain with pH below 5.5
Acidic oxide
Non metal oxide that is soluble in water
Basic oxide
Metal oxide that is soluble in water
Oxidation
The loss of electrons
Reduction
The gain of electrons
Functional Group
The part of a molecule that is responsible for its chemical (and sometimes physical) properties.
Why are atoms neutral?
They contain equal numbers of positive charges (protons) and negative charges (electrons)
What is Qualitative Analysis?
Used to determine what substances are present.
A flame test for example
What is Quantitative Analysis?
Used to determine the quantity of a substance in a sample.
A titration is used for quantitative analysis
Why can alkalis never have zero H+ (aq) ions present
Because alkalis are aqueous solutions and the dissociation of water means some H+ ions must be present
Why can acids never have zero OH- (aq) ions present?
Because acids are aqueous solutions and the dissociation of water means some OH- ions must be present
Give 2 advantages of neutralising with a metal carbonate instead of a metal oxide
- Reaction rate is high enough that acid doesn’t need to be heated
- Easier end point detection due to evolution of CO2
What does group number tell you?
The number of electrons in outer shell