Презентация на тему Ionization Energy

remove an electron from a gaseous atom.
An atom's 'desire'

to grab another atom's electrons.
Removing one electron makes a +1 ion.
The energy required is called the first ionization energy.
X(g) + energy →X+ + e-

be represented as follows:
 X+ (g) + energy? X2+ (g)

+ e-
X2+ (g) + energy? X3+ (g) + e-
More energy required to remove 2nd electron, and still more energy required to remove 3rd electron

outer electron is in the 3s sub-shell rather than

the 2s. This is higher in energy
The 3s electron is further from the nucleus and shielded by the inner electrons
So the 3s electron is more easily removed
A similar decrease occurs in every group in the periodic table.

a period
Look at the peak at Mg and the

plateau between P and S. Can you explain why?

Al?
 Al has configuration 1s2 2s2 2p6 3s2 3p1, its

outer electron is in a p sublevel
 Mg has electronic configuration 1s22s22p63s2.
 The p level is higher in energy and with Mg the s sub level is full – this gives it a slight stability advantage

S?

 This can be explained in terms of electron

pairing.
 As the p sublevel fills up, electrons fill up the vacant sub levels and are unpaired.
This configuration is more energetically stable than S as all the electrons are unpaired. It requires more energy to pair up the electrons in S so it has a lower Ionisation energy.
There is some repulsion between the paired electrons which lessens their attraction to the nucleus.
 It becomes easier to remove!

Gases have full energy levels.
Atoms behave in ways to

achieve noble gas configuration.

or half filled sublevel by removing 2 electrons 2nd

IE is lower than expected.
Makes it easier to achieve a full outer shell
True for s2
Alkaline earth metals form +2 ions.