unit 1 section 1 Atomic Structure Flashcards
what is the relative mass of an electron
1/2000
what is an isotope
an atom with the same number of protons but a different number of neutrons
what is the relative atomic mass
it is the average mass of an atom of an element on a scale where carbon 12 is exactly 12
what is a mass spectrometer
it is a machine used to analyse elements or compounds
explain the two types of ionisation methods in mass spectrometry
electrospray ionisation- sample is dissolved in a volatile solvent and is pushed through a nozzle at high pressure. high voltage applied, each atom gains H+ ion and the solvent is removed.
electron impact - sample is vaporised. electron gun fires high energy electrons at it, knock of 1 electron from each particle, overall positive charge .
explain how the detector plate works
when the postively charged ion hits the negatively charged dectector plate an electrial current is generated and this is proportional to the abudance of the atom. this current is recorded and this can be used to produce a mass spectrum.
what is an orbital
a region in which an electron can exist
why do electrons in the same orbital have opposite spins
this is in order to reduce the amount of repulsion between the electrons
difference in chromium & copper electron configuration compared to others
they donate one of there 4s electrons to the 3d subshell
what is first ionisation energy
is the amount needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions
what are the factors that affect the ionisation energy and explain
nuclear charge - the ratio of proton in the nucleus to the electrons. more protons = stronger forces of attraction- pulls electrons closer
Distance - the forces of attraction decrease as the distance from the nucleus increases.
shielding - as number of electrons increases between the outer electron and the nucleus, the weaker the forces of attraction between outer electron.
trend in ionisation energy as you go down group 2
it decreases as the size of the atoms increase so the distance between the outer electron and nucleus increases. the amount of shielding increases as the amount of electrons between outer electron and nucleus increase therefore the forces of attraction becomes weaker and the ionisation energy is reduced
trend in ionisation energies across a period
they generally increase as the distance from nucleus and shielding stays the same but the nuclear charge increases meaning there more positive nucleus has stronger forces of attraction on the outer electrons.
why is the a dip in ionisation energy between group 2&3
the outer electron is being taken from a higher subshell which is further from the nucleus and so it would require less energy to remove.
there will also be slightly more shielding since there is a subshell below
why is there a dip in ionisation energies in group 5&6
this is because electrons begin to share orbitals therefore the repulsion between electrons means that less energy is required to remove them.
