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43 Cards in this Set
- Front
- Back
- 3rd side (hint)
Atomic Number |
the number of protons in the nucleus of an atom |
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mass number |
the number of particles (protons and neutrons) in the nucleus |
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Isotopes |
Atoms of the same element with different number of neutrons |
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Ion |
A positively or negatively charged atom or (covalently bonded) group of atoms (a molecular ion) |
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Relative isotopic mass |
The mass of an atom of an isotope compared with 1/12th the mass of an atom of carbon 12 |
atom of an isotope |
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Relative atomic mass |
the weighted mean mass of an atom of an element compared with 1/12th the mass of an atom of carbon 12 |
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Relative molecular mass (Mr) |
the weighted mean mass of a molecule compared with 1/12th the mass of an atom of carbon 12 |
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Relative Formula Mass |
the weighted mean mass of a formula unit compared with 1/12th the mass of an atom of carbon 12 |
formula unit |
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Shell |
A group of atomic orbitals with the same principle quantum number (main energy level) |
group of orbitals |
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Principle quantum number |
Number representing overall energy of each orbital which increases with the distance from the nucleus. sets of orbitals with same n value are referred to as electron shell or energy level |
overall energy of each orbital |
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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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sub-shell |
a group of the same atomic orbitals within a shell |
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Electron configuration |
arrangement of electrons within an atom |
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Octet rule |
the tendency for atoms to combine so that each has 8 electrons in its outer shell, either through sharing or transferring electrons. results in noble gas configuration |
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compound |
substance formed from two or more chemically bonded elements in a fixed ratio, usually shown by a chemical formula |
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ionic compound |
a compound in which electrons are transferred from one element to another to form an ionic bond. usually between a metal and a non-metal |
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ionic bond |
the electrostatic attraction between oppositely charged ions |
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giant ionic lattice |
a giant ionic lattice is a three-dimensional structure of oppositely charged ions, held together by strong ionic bonds. strong electrostatic forces of attraction between oppositely charged ions |
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Electronegativity |
an atom bonding electrons in a covalent bond |
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Polar bond |
a covalent bond where a difference in electronegativity has caused a shift in electron density |
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polar molecule |
a molecule containing polar bonds that are arranged so that the dipoles don't cancel each other out, causing the overall dipole to be created across the molecule |
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intermolecular forces |
an attractive (electrostatic) force between neighboring molecules |
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permanent dipole-dipole forces |
a weak attractive force between permanent dipoles in neighboring polar molecules |
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van der Waals' forces |
attractive forces between induced attractions in neighboring molecules |
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hydrogen bonds |
a hydrogen bond is a strong dipole-dipole attraction between: an electron-deficient hydrogen atom on one molecule and a lone pair of electrons on, O, F, N on a different molecule |
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Enthalpy, H |
the heat content that is stored in a chemical system |
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chemical system |
the reactants and products |
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surroundings |
what is outside the chemical system |
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exothermic |
a reaction in which the enthalpy of the product is smaller than the enthalpy of the reactants |
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Endothermic |
a reaction in which the enthalpy of the products is greater than the enthalpy of the reactants resulting in heat being taken in from the surroundings |
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enthalpy profile diagram |
a diagram for a reaction to compare the enthalpy of the reactants with the enthalpy of the products |
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Activation energy, Ea |
the minimum energy required to start a reaction by the breaking of bonds |
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standard enthalpy change of reaction |
the enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical reaction under standard conditions, all reactants and products being in their standard states |
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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 under standard conditions, all reactants and products being in their standard states |
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standard enthalpy of formation |
the enthalpy change that takes place when one mole of a compound is formed from ints constituent elements in their standard states in standard conditions, the enthalpy change of formation for an element is 0 kJ/mol |
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standard conditions |
a pressure of 100 kPa a stated temperature, usually 25 degrees celsius or 298 K and a concentration of 1.0 mol/dm-3 |
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standard state |
the physical state of a substance under the standard conditions |
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specific heat capacity |
the energy required to raise the temperature of 1g of a substance by 1 degree celsius |
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standard enthalpy change of neutralisation |
the enthalpy change when 1 mole of water is formed in the reaction between an acid and a base in their standard states and conditions |
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bond enthalpy |
the enthalpy change required to break and separate 1 mole of bonds in the molecules if a gas so that the resulting gaseous (neutral) particles exert no force on each other |
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average bond enthalpy |
the average enthalpy change that takes place when breaking by homolytic fission 1 mole of a given type of bond in the molecule of a gaseous species |
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hess' law |
if a reaction can take place by more than one route and the initial and final conditions are the sane, the total enthalpy change is the same for each route |
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hess cycle |
a diagram showing alternative routes between reactants and products which allows the indirect determination of an enthalpy change from other known enthalpy changes using hess' law |
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