mr rahal quiz Flashcards
equation for second ionisation energy of boron
B+(g) -> B2+(g) +e-
why is second ionisation energy of boron greater than first?
electron being removed is closer to nucleus
state if aluminium or magnesium has lower first IE
Al; outer electron in 3p orbital which is further away from nucleus; easier to remove
explain trend of first IE across a period
general increase; greater nuclear charge; similar shielding; stronger attraction for outer electrons
state the trend in first IE down a group
decrease; ions get bigger/ more shielding; less attraction for outer electron
why does oxygen have a lower ionisation energy than nitrogen
outer electron shares an orbital; electrons in the orbital repel so it is easier to remove
what did niels bohr add to the rutherford atomic model
electrons orbited the nucleus at specific distances
Kr reacts with F. state why this discovery was unexpected
Kr was thought to be an inert gas
explain how the Ar can be calculated from data obtained from mass spectrum
spectrum gives relative abundance and m/z;
multiply m/z by relative abundance for each isotope;
find the sum;
divide by the sum of relative abundances
relative atomic mass
average mass atoms of an element relative to 1/12 the mass of C12
relative isotopic mass
the mass of an atom of an isotope relative to 1/12 the mass of C12
explain why is necessary to ionise molecules when measuring their mass in TOF
ions will be accelerated by an electric field; only ions will create a current when it hits the detector
electron impact ionisation meaning
high energy electrons from an electron gun are used to knock off electrons from each molecule or atom
state how the relative abundance of an ion is determined in a TOF spectrometer
ion gains electron at the detector;
abundance depends on the size of the current
meaning of electrospray ionisation
sample dissolved in volatile solvent; injected through a fine hypodermic needle giving off a fine mist; tip of the needle has a high voltage; each molecule gains a proton
