ionisation energies and electronic structure Flashcards
ionisation is when
energy is needed to pull the electron away from atom to act against the attraction between the electrons and nucleus.
the first ionisation energy ( triangle Hie1) is
the energy required to remove one mole of electrons from one mole of gaseous atoms.
the second ionisation energy ( triangle Hie2) is
the energy required to remove one mole of electrons from one mole of gaseous (+1) ions
why is more energy required to get rid of some electrons of certain atoms than others?
this is because the higher the proton number, the greater the force of attraction between the P and the E
Why does it get increasingly difficult for atoms to become ionised after losing the first electron?
because electrons are being removed from positive ions rather than neutral atoms
-this means that the negatively charged electrons will be more strongly held as the positive charge gets higher.
what shows the presence of electron shells?
the large jumps in IE after the first and ninth shell.
why is the first electron easily removed?
this is because it is furthest away from N.
the outer shell electron is shielded from the nucleus by the inner shell electrons and so experiences less nuclear attraction.
how can ionisation of certain atoms be shown?
on a successive ionisation energy graph
whats further evidence of the existence of electron shells?
arises from coloured flames some compounds give when placed on a bunsen burner
how do some compounds give out light when placed under a burner?
the ions absorb heat
this energy promotes an electron from its normal shell to the higher shell further from the nucleus.
when the electron falls back to the lower shell, it releases its extra energy in the form of visible light.
-the light released has different frequencies depending on the position of the electron shells- these frequencies are seen as colour.
quantum mechanics shows that electrons are divided into
subshells.
the subshells are then divided up into atomic orbitals
how many types of subshells are there
4 types
1) s= 2E
2) p= 6E
3) d=10E
4) f= 14E
what is the Aufbau Principle?
a set of rules that show how electrons must be placed in shells, subshells and orbitals.
rules of the Aufbau principle
1) each subshell must be completely filled before another is started
2) the 4s subshell is slightly closer to the nucleus than the 3rd subshell and must be filled first
3) when filling subshells, each orbital must be half filled before electrons are doubled up in pairs
4) when two electrons are in the same orbital, they must spin in opposite directions to overcome repulsion between their negative charges.
what is an s block element?
p orbital?
- has its outer most electron in an s orbital
- outermost electron in p orbital.
