atomic structure Flashcards
relative mass of neutron
1
relative mass of electron
1/1840
ionisation energy
amount of energy required to remove one mole of electrons from a mole of atoms in a gaseous state.
what are the two deviations in IE across period 3
aluminium and sulphur
ionisation energy
amount of energy needed to remove one mole of electrons from a mole of atoms in a gaseous state
why is lithium bigger than fluorine
Both Li + F have the same no of shells; same shielding effect
But F has more protons causing the force of attraction to be stronger to the nucleus effecting the outer shell
why is a lithium ION(+) smaller than a fluorine ION(-)
Lithium has 1 less shell; less shielding causing the nucleic attraction to be stronger than F- . Even tho F- has more protons .the electron shells shielding overcomes the attraction
chromium atom electron configuration
1s2 2s2 3s2 3p6 4s1 3d5
copper electron configuration
1s2 2s2 3s2 3p6 4s1 3d10
why is boron 1st IE lower than Be 1st IE (period 2)
- The first e- removed from Be is from 2s sub level/shell
-The first e- removed from B is from a 2p subshell/level
-The 2s sub level is lower in energy than 2p sub level
-Therefore less E is needed to remove the e- from B
why is oxygen 1st IE lower than N 1st IE (period 2)
-The first e- removed from N is in the 2p sub level and is unpaired
-the first e- removed from O is also from 2p sub level,but it is from a paired orbital.
-this means O has a lower IE due to electron pair repulsion.
-therefore,less E is needed to remove the e- from O.
why is aluminium 1st IE lower than magnesium 1st IE (period 3)
-the first e- removed from Mg is from a 3s sub level
-the first e- removed from Al is from 3p sublevel
-the sub level is lower In energy than 3p.
-therefore less E is required to get rid of the outer e from Al
why does sulphur have a lower 1st IE than phosphorus
S has a pair of electrons in the 3p subshell causing repulsion between the electrons
however in P the first e- has no pairs causing no repulsion.
require less E to remove outer e from S
the method for electron impact ?
the sample is vaporised + high E e- fired at it
the high energy e- come form electron gun
knocks of 1 electron forming 1+ ion
the 1+ ion are then attracted to negative electric plate where they accelerated
method for electron spray ionisation
sample is disssoved in volatile solvent
injected thru fine hypodermic needle
forms fine mist
tip of the needle attached to positive terminal of high voltage power supply
particles are onside by gaining a proton
solvent evaporates away while XH+ ions attracted to negative plate where they accelerated
