module two Flashcards
what does an atom consist of?
a nucleus containing protons and neutrons
electrons orbiting the nucleus in shells
relative mass and charge of sub-atomic particles
proton mass = 1 charge = +1
neutron mass = 1 charge = 0
electron mass = 1/2000 charge = -1
atomic number
number of protons in an atom
mass number
number of protons and neutrons in an atom
isotopes
atoms of the same element with different number of neutrons
relative isotopic mass
mass of an atom of an isotope relative to 1/12th the mass of an atom of carbon-12
relative atomic mass
weighted mean mass of an atom of an element relative to 1/12th the mass of an atom of carbon-12
equation for relative atomic mass
Ar = (% abundance of isotope 1 x mass) + (% abundance of isotope 2 x mass) / 100
atomic orbital
a region within an atom, around the nucleus, that contains up to two electrons with opposite spins
shell
a group of orbitals with the same principle quantum number
sub-shell
a group of the same type of orbitals in a shell
s sub-shell
orbital is spherical
consists of one orbital
can hold up to 2 electrons
p sub-shell
orbital is dumbell shaped
consists of 3 orbitals
can hold up to 6 electrons
d sub-shell
consists of 5 orbitals
can hold up to 10 electrons
f sub-shell
consists of 7 orbitals
can hold up to 14 electrons
aufbau (building-up) principle
electrons fill orbitals of lowest energy first
order of filling: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10 4f14
why does 4s fill before 3d?
4s sub-shell has a lower energy than 3d sub-shell
blocks of the periodic table linking to electron structure
eg elements in s-block have their highest energy electron in an s sub-shell
common acid-base reactions
metal + acid -> salt + hydrogen
metal oxide + acid -> salt + water
metal hydroxide + acid -> salt + water
metal carbonate + acid -> salt + water + CO2
ammonia + acid -> ammonium salt
acid
proton (H+) donor
strong vs weak acids
a strong acid completely dissociates into its ions in aqueous solution
a weak acid partially dissociates into its ions in aqueous solution
base
proton (H+) acceptor
alkali
soluble base that releases OH- ions in aqueous solution
salt
produced when the H+ of an acid is replaced by metal or ammonium ions