Periodic table Flashcards
whats pauli exclusion principle
no two electrons can have the same 4 quantum numbers
whats aufbau principle
electrons are placed in the lowest energy permissable level
what is hunds rule
when filling a degenerate set of orbitals in the ground state
orbitals must all be filled with one electron until paired. when paired, they must have parallel spins.
how do you write out electron config of ions
for main group: normal
for transition metals: highest s group electrons removed first
what are the special cases
Ar]4s13d5 – chromium
o Cu [4s13d10
explain why they’re special cases
spin pairing energy: When two electrons are forced to occupy the same orbital, they experience a inter-electronic repulsion effect on each other which in turn increases the total energy of the orbital. Chromium’s electron arrangement prevents this from happening
describe effective nuclear charge (core charge)
as you go across periodic table
-no core electrons is constant
-no protons increases
therefore valence electrons can better penetrate nucleus and overcome shilelding of core electrons. higher core charge = smaller atomic radius
describe electron affinity
energy change required to add one mole of electrons to one mole of gaseous atoms or ions
- increases across a group as core charge increases because higher core charge so electrons omre likely to be attracted to nucleus
- decreases down a group because lower core charge, electrons less likely to be attracted to nucleus
describe ionisation energy
energy required to remove one mole of electrons from one mole of gaseous atoms/ions
- increases across a period as core charge increases - more energy to remove
- decreases down a group as valence electrons less attracted to nucleus - less energy to remove
successive ionisation energy
increases with each electron removed
large increase after all valence electrons are removed
