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68 Cards in this Set
- Front
- Back
Atomic number |
The number of protons in the nucleus of an atom. |
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Mass number |
The number of protons and neutrons in the nucleus of an atom. |
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Relative isotopic mass |
The mass of an atom of an isotope compared with 1/12 of the mass of an atom ofC-12. |
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Relative atomic mass |
The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of C-12. |
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Isotopes |
Atoms of the same element with a different number of neutrons. |
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Atomic orbital |
A region within an atom that can hold up to two electrons, with opposite spins. |
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s/p/d block element |
Highest energy sub-shell is a s/p/d sub-shell. |
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Acid |
Release H+ ions in solution (proton donor). |
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Base |
A proton acceptor. |
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Alkali |
A soluble base that release OH- ions when in solution. |
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Salt |
A compound produced when a H+ ion from an acid is replaced by a metalor another positive ion, such as the ammonium ion. |
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Mole |
The amount of substance containing as many particles as there are carbon atoms inexactly 12g of C-12. |
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Avagdro's constant |
The number of particles per mole of a substance (6.02x1023). |
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Molar mass |
The mass, in g, per mole of a substance. Units are gmol-1. |
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Empirical formula |
The simplest whole number ratio of atoms of each element present in a compound. |
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Molecular formula |
The actual number of atoms of each element in a molecule. |
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Waters of crystallisation |
The water present in a compound giving the compound a crystalline appearance. |
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Anhydrous |
When all the waters of crystallisation havebeen removed from a compound. |
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Hydrated |
When water of crystallisation is present in a crystal compound. |
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First ionisation energy |
The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions. Units are kJ mol-1. |
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Successive ionisation energy |
A measure of the energy required to remove each electron in turn. |
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Ionic bond |
The electrostatic attraction between oppositely charged ions. |
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Covalent bond |
The sharing of a pair of electrons between two atoms. |
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Dative (co - ordinate) bond |
The sharing of a pair of electrons between two atoms where only one of the atomssupplies both the electrons shared. |
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Electronegativity |
The ability of an atom to attract the bonding electrons towards itself in acovalent bond. |
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Metallic bonding. |
The attraction of positive metal ions to delocalised electrons. |
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Periodicity |
The repeating pattern of trends across different periods. |
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Oxidation number |
A measure of the number of electrons that an atom uses to bond with atoms of adifferent element. |
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Oxidation |
The loss of electrons / an increase in oxidation number (state). |
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Oxidising agent |
A reagent which oxidises another species (gets reduced itself). |
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Reduction |
The gain of electrons / a decrease in oxidation number (state). |
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Reducing agent |
A reagent which reduces another species (gets oxidised itself). |
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Redox |
A reaction where both oxidation and reduction take place. |
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Displacement reaction |
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of its halide ions. |
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Disproportionation |
A reaction in which an element is simultaneously oxidised and reduced. |
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Hydrogen bonds |
A dipole-dipole attraction between a slightly positive hydrogen on one molecule and a lone pair of electrons on a highly electronegative atom (N, O, F) of another molecule. |
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Hydrocarbon |
A compound containing only hydrogen and carbon only. |
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Homologous series |
A series of organic compounds having the same functional group but with each successive member differing by CH2. |
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Functional group |
A group of atoms responsible for the characteristic reactions of a compound. |
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Saturated |
Containing single bonds only. |
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Unsaturated |
Containing at least one carbon - carbon double bond. |
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Empirical formula |
The simplest whole number ratio of atoms of each element present in a compound. |
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Molecular formula |
The actual number of atoms of each element in a molecule. |
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Structural isomers. |
Compounds with the same molecular formula but a different structural formula. |
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Stereoisomers |
Compounds with the same structural formula but a different arrangement of atoms in the space. |
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E/Z Isomerism |
An example of stereoisomerism, in terms of restricted rotation about a double bond and the requirement for two groups to be attached to each carbon of the carbon - carbon double group. |
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CIS - TRANS Isomerism |
A special case of E/Z isomerism in which two of the substituent groups are the same. |
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Fractional distillation |
Separation of a liquid mixture into fractions with different boiling points. |
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Catalytic cracking |
The breaking down of long chained saturated hydrocarbons to form more useful and shorter chained alkanes and alkenes. |
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Biofuel |
A fuel that is derived from recently living material such as plants or from the waste of animals. |
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Curly arrow |
The movement of an electron pair, showing either the breaking or formation of a covalent bond |
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Radical |
A species with an unpaired electron. |
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Homolytic fission |
The breaking of a covalent bond where the shared pair of electrons are split equally forming two radicals. |
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Heterolytic fission |
The breaking of a covalent bond where the shared pair of electrons are not equally split, forming a cation and an anion. |
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Electrophile |
Species attracted to an electron rich centre where it accepts a pair of electrons to form a new covalent bond. |
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Nucleophile |
A species that is attracted to an electron deficient centre where it donates a pair of electrons to form a new covalent bond. |
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Exothermic |
Heat is given out to the surroundings (reactants lose energy). |
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Endothermic |
Heat is taken from the surroundings (reactants gain energy). |
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Activation energy |
The minimum energy required to start a reaction by the breaking of bonds. |
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Standard conditions |
A pressure of 1 atmosphere, 25 degrees celcius, and a concentration of 1.00 moldm - 3. |
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Standard enthalpy change of reaction |
The enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation (under standard conditions). |
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Standard enthalpy change of formation |
The enthalpy change that takes place when one mole of a compound is formed from its constituent elements (in standard conditions). |
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Standard enthalpy change of combustion |
The enthalpy change that takes place when one mole of a substance reacts completely with oxygen (in standard conditions). |
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Average bond enthalpy |
The average enthalpy change that takes place when breaking by homolytic fission, one mole of a given type of bond in the molecules of a gaseous species. |
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Catalyst |
Speeds up a reaction without being consumed by the overall reaction. |
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Volatility |
The ease at which a liquid turns into a gas. |
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Dynamic equilibrium |
The equilibrium that exists in a closed system when the rate of forward reaction is equal to the rate of the reserve reaction. |
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Le Chatelier's principle |
When a system in dynamic equilibrium is subjected to change, the position of equilibrium will shift to minimise the change. |