1. Orbitals
Electron Configurations
Orbitals

2. Orbitals Orbitals s orbital p orbital
AS Jun-2015

3. Orbitals Orbitals Sub-level Number of orbitals in sub-level
Shape (no need to learn)
Maximum number of electrons in sub-level s 1 2 p 3 6 d 5 10 f 7
Even more complicated! 14
Orbitals
Electrons
© AS Jun-2015

4. Electron Configurations
Orbitals
Electron Configurations
The electrons are found orbitals or electron configurations.
They follow 3 rules:
The Aufbau Principle
The Paulie Exclusion Principle
Hunds Rule
Orbitals
Electrons

5. Orbitals
The Aufbau Principle- says that orbitals are “filled” from the “bottom” to the “top”, or electrons will fill the orbitals with lower energy first
Nucleus
First Orbital
Second Orbital
Orbitals
Electrons

6. Orbitals Orbitals 1s 2s 2p 3p 3s 4s
The Paulie Exclusion Principle- says that only two electrons can reside in any one orbital AND they must have opposite spin directions
Hunds Rule:
Every orbital has a single occupied orbital BEFORE
it is doubled. AND the electrons single electrons have the same spin 1s 2s 2p 3p 3s 4s
Orbitals
Electrons

7. Arrangement of the Orbitals
Aufbau Principle
Some other needed knowledge
Each Orbital belongs to a “Principle Energy Level”
There are 4 main subtypes of orbitals in an atom
s, p, d, and f. And the energy goes s>p>d>f
There is 1 s orbital, 3 p orbitals, 5 d orbitals and 7 F’s
There arrangement follows the periodic table
Or does the periodic table follow their arrangement???
Aufbau Principle
Electrons

8. Aufbau Principle Aufbau Principle
Electrons

9. Electron Configurations
Aufbau Principle
Electron Configurations
You try a orbital filling diagram of the oxygen atom.
Electron Configurations of Selected Elements
Element 1s 2s
2px 2py 2pz 3s
Electron configuration H
1s1 He
1s2 Li
1s22s1 C
1s22s22p2 N
1s22s22p3 O
1s22s22p4 F
1s22s22p5 Ne
1s22s22p6 Na
1s22s22p63s1
Notice: each of the three 2p orbitals has one electron. The remaining electron now pairs with an electron occupying one of the 2p orbitals.

10. Aufbau Principle Orbitals
CHEMISTRY & YOU
Explain why the correct electron configuration of oxygen is 1s22s22p4
and not
1s22s22p33s1.
Answer: it does not obey the Aufbau Principle
Orbitals
Electrons

11. Aufbau Principle of Phosphorous
Sample Problem 5.1
The atomic number of phosphorus is 15. Write the electron configuration of a phosphorus atom. 1s 2s 2p 3p 3s 4s
The electron configuration of phosphorus is 1s22s22p63s23p3.
The superscripts add up to the number of electrons.
Electrons

12. Electron Configurations
Exceptional Electron Configurations.
Electron Configurations
This is what a usual one looks like
Cr 1s22s22p63s23p63d44s2
Cu 1s22s22p63s23p63d94s2
The correct electron configurations are as follows:
Cr 1s22s22p63s23p63d54s1
Cu 1s22s22p63s23p63d104s1
These arrangements give chromium a half-filled d sublevel and copper a filled d sublevel- This is because filled and half filled orbitals are more stable
Orbitals
Electrons

13. Orbitals
What is the correct electron configuration of a sulfur atom?
A. 1s22s22p43s23p6
B. 1s22s22p63s23p3
C. 1s22s22p63s23p4
D. 1s22s22p63s63p2
Orbitals
Electrons

14. Orbitals
What is the correct electron configuration of a sulfur atom?
A. 1s22s22p43s23p6
B. 1s22s22p63s23p3
C. 1s22s22p63s23p4
D. 1s22s22p63s63p2
Orbitals
Electrons

15. Ionization Energy Ionization Energy What is ionisation energy?
Definitions
Film Clip
Ionization Energy
Electrons

16. WHAT IS IONISATION ENERGY?
Ionization Energy
WHAT IS IONISATION ENERGY? -
Attraction between the nucleus and an electron
Ionisation Energy is a measure of the amount of energy needed to remove electrons from atoms.
The greater the pull of the nucleus, the harder it will be to pull an electron away from an atom.
FIRST IONISATION ENERGY - Definition
The energy required to remove ONE MOLE of electrons from each atom in ONE MOLE of gaseous atoms to form ONE MOLE of gaseous positive ions.
e.g. Na(g) Na+(g) + e-
Al(g) Al+(g) + e-
Make sure you write in the (g)
Ionization Energy
Electrons

17. Successive Ionisation Energies
Ionization Energy
Successive Ionisation Energies
What does this mean to you?
Mg(g)  Mg+(g) + e- 1st I.E. =+738 kJ.mol-1
Mg+(g)  Mg2+(g) + e- 2nd I.E.= kJ.mol-1
Mg2+(g)  Mg3+(g) + e- 3rd I.E.= kJ.mol-1
Ionization Energy
Electrons

18. Ionization Energy
1st ionisation energy. What is happening across the table? AND Down the noble gases
Li 520
Na 496
K 419
Rb 408
Cs 376

19. Ionization Energy - Groups
Ionization energies decrease going down a Group, Why?
1) Moving down a group the principle energy level increases
distance of electron from the pull of the positive nucleus
2) AND here are more electrons providing inner shell shielding of the
nucleus. Therefore the valence electrons are less strongly held
Na (IE = 496 KJ/Mol) Rb (IE = 403 KJ/mol)
Ionization Energy

20. 1st ionisation energy (across period)
Orbitals
1st ionisation energy (across period)
Atomic Radius DECREASES, why?
Increased nuclear charge (i.e. more protons)
Thus a stronger attraction from nucleus to electron in outer shell
Atoms get smaller
Orbitals
Electrons
© AS Jun-2015

21. Ionization Energy Trends
Orbitals
General Trends
Ionization energy increases as each successive
electron is removed
2) Ionization energy DECREASES going DOWN a GROUP
3) Ionization energy INCREASES as you go ACROSS a
PERIOD
4) The noble gases have the highest Ionization energies
5) The alkali metals have the lowest Ionization energies
Orbitals

22. Ions Orbitals https://www.youtube.com/watch?v=vp9mfW7dqE0
IONS FORM by:
ALWAYS removing the highest level of n.
Or the highest energy electrons are lost when an ion is formed. AND the energy is as follows:
least s<p<d<f (most)
Orbitals
Electrons
© AS Jun-2015

23. ELECTRONIC CONFIGURATION OF IONS
3 Things:
Positive ions (cations) are formed by removing electrons from atoms
Negative ions (anions) are formed by adding electrons to atoms
Electrons are removed first from the highest occupied orbitals
SODIUM Na 1s2 2s2 2p6 3s electron removed from the 3s orbital
Na+ 1s2 2s2 2p6
CHLORINE Cl 1s2 2s2 2p6 3s2 3p electron added to the 3p orbital
Cl¯ 1s2 2s2 2p6 3s2 3p6
Anions are always larger than their parent atom.
Cations are always smaller than their parent atom.
Ions

24. ELECTRONIC CONFIGURATION OF IONS FIRST ROW TRANSITION METALS
Despite being of lower energy and being filled first, electrons in the 4s orbital are removed before any electrons in the 3d orbitals.
TITANIUM Ti 1s2 2s2 2p6 3s2 3p6 4s2 3d2
Ti+ 1s2 2s2 2p6 3s2 3p6 4s1 3d2
Ti2+ 1s2 2s2 2p6 3s2 3p6 3d2
Ti3+ 1s2 2s2 2p6 3s2 3p6 3d1
Ti4+ 1s2 2s2 2p6 3s2 3p6
Ions