Chemistry Key Words Flashcards
(26 cards)
Mass number
The mass number of an atom is the sum of the number of protons and the number of neutrons in the nucleus of the atom
Isotopes
Isotopes are atoms of the same element with different masses they have the same number of protons but different number of neutrons
Relative isotopic mass
The mass of an atom of an isotope of an element compared to 1/12 of the mass of an atom of carbon 12 which has a mass of 12
Relative Atomic mass
Relative atomic mass of an element is the weighted mean mass of an atom and of the element compare to 1/12 of the mass of an atom of carbon 12 which has a mass of 12
Molecular ion peak
The molecular ion peak is the peak with the highest M/z ratio in the mass spectrum
Quantum shell
A quantum shell defines the energy level of an electron
Orbital
And orbital is a region within an atom that can hold up to 2 electrons with opposite spins
Electronic configuration
The electronic configuration of an atom shows number of electrons in each sub level in each energy level of the atom
First ionisation energy
The first ionisation energy of an element is the energy required to remove an electron from each atom in one mole of atoms in the gaseous state
Periodicity
Periodicity is a regularly repeating pattern of Atomic, physical and chemical properties with increasing atomic number
Metallic bonding
Metallic bonding is the electrostatic force of attraction between the nuclei of metal cations and delocalised electrons
Bond length
Bond length is the distance between the nuclei two atoms that are covalently bonded together
Electronegativity
Electronegativity is the ability of an atom to attract the bonding pair of electrons in a covalent bond
Polar covalent bond
A polar covalent bond is the type of covalent bond between two atoms whether bonding electrons are equally distributed. Because of this, one at in carries a slight negative charge and the other a slight positive charge
Dipole
A dipole is said to exist when two charges of equal magnitude but opposite signs are separated by a small distance
Atomic number
The Atomic number of an element is the number of protons in the nucleus of an atom of of that element
Mole
A mole is the amount of substance that contains the same number of particles as the number of carbon atoms in exactly 12 g of carbon 12 isotope
Theoretical yield
The theoretical yield in a reaction is the maximum possible mass of the product, assuming complete reaction and no losses
Actual yield
The actual yield in a reaction is the actual mass obtained
Standard enthalpy change of reaction
The end of the change measured at hundred KPa and a stated temperature, usually 298K, when the number of moles of substance in an equation as written react
Standard enthalpy change of combustion
Is the enthalpy change measured at 100KPa and a stated temperature, usually 298K when one mole of substance is completely burned in oxygen
Standard enthalpy change of neutralisation
Is the Engleby change measured at 100KPa and a stated temperature usually 298K, when one mole of water is produced by the neutralisation of an acid with an alkali
Standard enthalpy change of formation
Is the enthalpy change measured at 100KP and a specified temperature usually 298K when one mole of a substance is formed from its elements in their standard states
Hess’s Law
Hess’s law states that the enthalpy change of reaction is independent of the path taken in converting reactants and products, provided the initial and final conditions are the same in each case
