definitions Flashcards
atomic number
no of protons in the nucleus
mass number
number of protons and neutrons in the nucleus
isotope
atoms of the same element with the same number of protons, but different numbers of neutrons.
relative isotopic mass
the mass of one isotope compared to one twelfth of the mass of one atom of carbon-12
relative atomic mass
the weighted mean mass of one atom compared to one twelfth of the mass of one atom of carbon-12
relative molecular mass
the average mass of a molecule compared to one twelfth of the mass of one atom of carbon-12
the mole
the amount of substance in grams that has the same number of particles as there are atoms in 12 grams of carbon-12.
molar mass
the mass in grams of 1 mole of a substance and is given the unit of g mol-1
molar gas volume
the volume of 1 mole of a gas at a given temperature and pressure.
avogadro’s constant
There are 6.02 x 1023 atoms in 12 grams of carbon-12.
empirical formula
the simplest ratio of atoms of each element in the compound
molecular formula
the actual number of atoms of each element in the compound.
acid
releases H+ ions in aqueous solution
Bronsted- Lowry base
a proton (H+) acceptor
Bronsted- Lowry acid
a proton donor
alkali
soluble base that releases OH- ions in aqueous solution
strong acids
completely dissociate when dissolved in water
weak acid
slightly dissociate when dissolved in water, giving an equilibrium mixture
salt
formed when the H+ ion of an acid is replaced by a metal ion or an ammonium ion
oxidation
process of electron loss
results in an increase in oxidation number
reduction
process of electron gain
involved a decrease in oxidation number
ionic bonding
the electrostatic force of attraction between oppositely charged ions formed by electron transfer.
covalent bonding
the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
dative covalent bond
when the shared pair of electrons in the covalent bond come from only one of the bonding atoms.
electronegativity
the relative tendency of an atom in a covalent bond in a molecule to attract electrons in a covalent bond to itself.
periodicity
a repeating pattern across different periods
first ionisation energy
the Energy needed to remove an electron from each atom in one mole of gaseous atoms