Electron Config + Ionisation Energies Flashcards
what are the 3 blocks of the periodic table and how many electrons can each of them hold?
s block = 2
p block = 6
d block = 10
example:
Na = 1s2, 2s2, 2p6, 3s1
Copper = [Ar] 4s1, 3d10
Chromium = [Ar] 4s1, 3d5
Ionisation energy definition
the minimum energy required to remove one mole of electrons from one mole of atoms in a gaseous state.
measured in KJmol-1
What is the first ionisation energy trends
Along a period: increases bc the atomic radius decreases therefore GREATER electrostatic FoA.
Down a group: decreases bc the atomic radium increases due to more shielding therefore LOWER electrostatic FoA.
What can successive ionisation energies on a graph tell you?
Able to identify an element.
A sudden large increase in the graph means a change in energy level (removing an electron from an internal shell)
this means that more energy is needed to break the electrostatic forces between the positive nucleus and the negative outer electron.
watch “successive ionisation energies” by freesciencelessons
explain how first and successive ionisation energies in Period 3 (Na-Ar) give evidence for electron configuration in sub-shells and in shells.
Mg and Al - there is a decrease because the Al is in a 3p orbital (a higher energy level - further away from the nucleus) therefore this requires less energy to remove.
P and S - there is a decrease.
In phosphorus: there is only one electron in each of 3p orbital therefore there is no repulsion - it is stable.
In sulfur: in one of the 3p orbitals contains 2 electrons so repulsion is present. The repulsion between the paired electrons makes it easier to remove 1 electron therefore it requires less ionisation energy.
Explain how first and successive ionisation energies in Group 2 (Be-Ba) give evidence for electron configuration in sub-shells and in shells.
In group 2: decreases bc the atomic radium increases due to more shielding therefore LOWER electrostatic FoA.
