U1S1 ionisation energies Flashcards
1
Q
First ionisation energy
A
- energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions
2
Q
What factors increase ionisation energy
A
- higher nuclear charge
- shorter distance from nucleus
- lower shielding
3
Q
Second ionisation energy
A
- energy needed to remove an electron from each atom in 1 mole of gaseous 1+ ions
4
Q
Why is second ionisation energy greater than first ionisation energy
A
- electron being removed from an ion rather than an atom
- requires more energy
5
Q
Ionisation trend down group 2
A
- decreases
- provides energy of shells
6
Q
Ionisation trend across periods
A
- general increase
- proton number increasing
7
Q
Why is there a drop in ionisation energy between group 2 and 3
A
- aluminiums outer electron nis in a 3p orbital rather than 3s
- higher energy level so electron further from nucleus
- additional shielding by 3s electrons
8
Q
Why is there a drop in ionisation energy between group 5 and 6
A
- phosphorus being removed from a singly occupied orbital and in sulfur is being removed from a doubly occupied orbital
- electron repulsion means its easier to remove from shared orbitals
9
Q
What does successive ionisation energy provide evidence of
A
- the shell structure of atoms
