1. Draw a dot-cross diagram for a sodium atom 2. Write an equation to show the first ionisation energy of sodium (its value is +496kJmol -1 ) 3. Write an equation to show the fifth ionisation energy of sodium (+13352kJmol -1 ) 4. Why are they such different values? (3 main factors) How much can you remember from last lesson?
1.Draw a dot-cross diagram for a sodium atom 2.Write an equation to show the first ionisation energy of sodium (its value is +496kJmol -1 ) 3.Write an.
Jan 05, 2016
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1. Draw a dot-cross diagram for a sodium atom
2. Write an equation to show the first ionisation energy of sodium (its value is +496kJmol-1)
3. Write an equation to show the fifth ionisation energy of sodium (+13352kJmol-1)
4. Why are they such different values? (3 main factors)
How much can you remember from last lesson?
To Learn Today
• What are electron orbitals?
• What are shells and sub-shells?
• What is the principal quantum number?
• How can we write electron
configurations?
• How are they all related to the periodic
table?
THE BOHR ATOMTHE BOHR ATOM
Maximum electrons per shell
1st shell 2
2nd shell 8
3rd shell 18
4th shell 32
5th shell 50
Energy Levels increase further from the nucleus
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Shells of ElectronsShells of ElectronsPRINCIPAL ENERGY LEVELS
•Hydrogen was studied
•The gaps between energy levels were not equal
•The closer to the nucleus, the closer together the energy levels were
HEISENBERG’S UNCERTAINTY PRINCIPLE
“You cannot determine the position and momentum of an electron at the same time.”
This means that you cannot say exactly where an electron is. It put paid to the idea of electrons orbiting the nucleus in rings and introduced the idea of orbitals.
Sketch a probability cloud for the football on the pitch
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SLEVELS AND SUB-LEVELSLEVELS AND SUB-LEVELS
A study of Ionisation Energies and the periodic properties of elements suggested that the main energy levels were split into sub shells.
Level 1 was split into 1 sub shell
Level 2 was split into 2 sub shells
Level 3 was split into 3 sub shells
Level 4 was split into 4 sub shells
SUB SHELLSPRINCIPAL SHELLS
RULES AND PRINCIPLESRULES AND PRINCIPLES
THE AFBAU PRINCIPLE
“Electrons enter the lowest available energy level.”
PAULI’S EXCLUSION PRINCIPLE
“No two electrons can have the same four quantum numbers.”
Two electrons can go in each orbital, providing they are of opposite spin.
HUND’S RULE OF MAXIMUM MULTIPLICITY
“When in orbitals of equal energy, electrons will try to remain unpaired.”
“SITTING ON A BUS RULE”!
ATOMIC ORBITALSATOMIC ORBITALS
An orbital is... a region in an ATOM that can hold up to TWO ELECTRONS, with OPPOSITE SPINS
ORBITALSORBITALS
An orbital is... a region in space where one is likely to find an electron. a region in space where one is likely to find an electron.
Orbitals can hold up to two electrons as long as they have opposite spin; this is known as PAULI’S EXCLUSION PRINCIPAL.
Orbitals have different shapes...
ORBITAL SHAPE OCCURRENCE
s spherical one in every principal level
p dumb-bell three in levels from 2 upwards
d various five in levels from 3 upwards
f various seven in levels from 4 upwards
ORBITALSORBITALS
An orbital is... a region in space where one is likely to find an electron. a region in space where one is likely to find an electron.
Orbitals can hold up to two electrons as long as they have opposite spin; this is known as PAULI’S EXCLUSION PRINCIPAL.
Orbitals have different shapes...
ORBITAL SHAPE OCCURRENCE
s spherical one in every principal level
p dumb-bell three in levels from 2 upwards
d various five in levels from 3 upwards
f various seven in levels from 4 upwards
An orbital is a 3-dimensional statistical shape showing where one is most likely to find an electron. Because, according to Heisenberg, you cannot say exactly where an electron is you are only able to say where it might be found.
DO NOT CONFUSE AN ORBITAL WITH AN ORBIT
SHAPES OF ORBITALSSHAPES OF ORBITALS
s orbitals
• spherical
• one occurs in every principal energy level
•s = ‘sharp’
SHAPES OF ORBITALSSHAPES OF ORBITALS
p orbitals
• dumb-bell shaped
• three occur in energy levels except the first
•p = ‘principal’
SHAPES OF ORBITALSSHAPES OF ORBITALS
d orbitals
• various shapes
• five occur in energy levels except the first and second
•d = ‘diffuse’
Orbitals are not filled in numerical order because the principal energy levels get closer together as you get further from the nucleus. This results in overlap of sub levels. The first example occurs when the 4s orbital is filled before the 3d orbitals.
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1 1s
22s
2p
4s
33s3p3d
44p
4d4f
PRINCIPAL ENERGY LEVELS
SUB LEVELS
ORDER OF FILLING ORBITALSORDER OF FILLING ORBITALS
Orbitals are not filled in numerical order because the principal energy levels get closer together as you get further from the nucleus. This results in overlap of sub levels. The first example occurs when the 4s orbital is filled before the 3d orbitals.
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1 1s
22s
2p
4s
33s3p3d
44p
4d4f
PRINCIPAL ENERGY LEVELS
SUB LEVELS
1 1s
22s
2p
3d
33s3p4s
44p
4d4f
PRINCIPAL ENERGY LEVELS
SUB LEVELS
ORDER OF FILLING ORBITALSORDER OF FILLING ORBITALS
Orbitals are not filled in numerical order because the principal energy levels get closer together as you get further from the nucleus. This results in overlap of sub levels. The first example occurs when the 4s orbital is filled before the 3d orbitals.
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1 1s
22s
2p
4s
33s3p3d
44p
4d4f
PRINCIPAL ENERGY LEVELS
SUB LEVELS
1 1s
22s
2p
3d
33s3p4s
44p
4d4f
PRINCIPAL ENERGY LEVELS
SUB LEVELS
ORDER OF FILLING ORBITALSORDER OF FILLING ORBITALS
THE FILLING ORDER
1s
2s 2p
3s 3p 3d
4s 4p 4d 4f
5s 5p 5d 5f
6s 6p 6d
7s 7p
HOW TO HOW TO REMEMBER ..REMEMBER ....
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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This states that…
“ELECTRONS ENTER THE LOWEST AVAILABLE
ENERGY LEVEL”
THE ‘AUFBAU’ PRINCIPALTHE ‘AUFBAU’ PRINCIPAL
The following sequence will show the ‘building up’ of the electronic structures of the first 36 elements in the periodic table.
Electrons are shown as half headed arrows and can spin in one of two directions
or
s orbitals
p orbitals
d orbitals
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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HYDROGEN
1s1
THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
Hydrogen atoms have one electron. This goes into a vacant orbital in the lowest available energy level.
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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HELIUM
1s2
THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
Every orbital can contain 2 electrons, provided the electrons are spinning in opposite directions. This is based on...
PAULI’S EXCLUSION PRINCIPLE
The two electrons in a helium atom can both go in the 1s orbital.
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
LITHIUM
1s orbitals can hold a maximum of two electrons so the third electron in a lithium atom must go into the next available orbital of higher energy. This will be further from the nucleus in the second principal energy level.
The second principal level has two types of orbital (s and p). An s orbital is lower in energy than a p.
1s2 2s1
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
BERYLLIUM
Beryllium atoms have four electrons so the fourth electron pairs up in the 2s orbital. The 2s sub level is now full.
1s2 2s2
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
BORON
As the 2s sub level is now full, the fifth electron goes into one of the three p orbitals in the 2p sub level. The 2p orbitals are slightly higher in energy than the 2s orbital.
1s2 2s2 2p1
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
CARBON
The next electron in doesn’t pair up with the one already there. This would give rise to repulsion between the similarly charged species. Instead, it goes into another p orbital which means less repulsion, lower energy and more stability.
1s2 2s2 2p2
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
NITROGEN
Following Hund’s Rule, the next electron will not pair up so goes into a vacant p orbital. All three electrons are now unpaired. This gives less repulsion, lower energy and therefore more stability.
1s2 2s2 2p3
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
OXYGEN
With all three orbitals half-filled, the eighth electron in an oxygen atom must now pair up with one of the electrons already there.
1s2 2s2 2p4
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
FLUORINE
The electrons continue to pair up with those in the half-filled orbitals.
1s2 2s2 2p5
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
NEON
The electrons continue to pair up with those in the half-filled orbitals. The 2p orbitals are now completely filled and so is the second principal energy level.
In the older system of describing electronic configurations, this would have been written as 2,8.
1s2 2s2 2p6
1 1s
22s
2p
4s
3
3s
3p
3d
44p
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4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
SODIUM - ARGON
With the second principal energy level full, the next electrons must go into the next highest level. The third principal energy level contains three types of orbital; s, p and d.
The 3s and 3p orbitals are filled in exactly the same way as those in the 2s and 2p sub levels.
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
SODIUM - ARGON
Na 1s2 2s2 2p6 3s1
Mg 1s2 2s2 2p6 3s2
Al 1s2 2s2 2p6 3s2 3p1
Si 1s2 2s2 2p6 3s2 3p2
P 1s2 2s2 2p6 3s2 3p3
S 1s2 2s2 2p6 3s2 3p4
Cl 1s2 2s2 2p6 3s2 3p5
Ar 1s2 2s2 2p6 3s2 3p6
Remember that the 3p configurations follow Hund’s Rule with the electrons remaining unpaired to give more stability.
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
POTASSIUM
In numerical terms one would expect the 3d orbitals to be filled next.
However, because the principal energy levels get closer together as you go further from the nucleus coupled with the splitting into sub energy levels, the 4s orbital is of a LOWER ENERGY than the 3d orbitals so gets filled first.
1s2 2s2 2p6 3s2 3p6 4s1
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
CALCIUM
As expected, the next electron pairs up to complete a filled 4s orbital.
This explanation, using sub levels fits in with the position of potassium and calcium in the Periodic Table. All elements with an -s1 electronic configuration are in Group I and all with an -s2 configuration are in Group II.
1s2 2s2 2p6 3s2 3p6 4s2
‘Aufbau’
Principle
‘Aufbau’
Principle
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
SCANDIUM
With the lower energy 4s orbital filled, the next electrons can now fill the 3d orbitals. There are five d orbitals. They are filled according to Hund’s Rule -
BUT WATCH OUT FOR TWO SPECIAL CASES.
1s2 2s2 2p6 3s2 3p6 4s2 3d1
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
TITANIUM
1s2 2s2 2p6 3s2 3p6 4s2 3d2
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
The 3d orbitals are filled according to Hund’s rule so the next electron doesn’t pair up but goes into an empty orbital in the same sub level.
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
VANADIUM
The 3d orbitals are filled according to Hund’s rule so the next electron doesn’t pair up but goes into an empty orbital in the same sub level.
1s2 2s2 2p6 3s2 3p6 4s2 3d3
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
CHROMIUM
One would expect the configuration of chromium atoms to end in 4s2 3d4.
To achieve a more stable arrangement of lower energy, one of the 4s electrons is promoted into the 3d to give six unpaired electrons with lower repulsion.
1s2 2s2 2p6 3s2 3p6 4s1 3d5
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
MANGANESE
The new electron goes into the 4s to restore its filled state.
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1s2 2s2 2p6 3s2 3p6 4s2 3d5
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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IRON
Orbitals are filled according to Hund’s Rule. They continue to pair up.
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1s2 2s2 2p6 3s2 3p6 4s2 3d6
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
COBALT
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1s2 2s2 2p6 3s2 3p6 4s2 3d7
Orbitals are filled according to Hund’s Rule. They continue to pair up.
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
NICKEL
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1s2 2s2 2p6 3s2 3p6 4s2 3d8
Orbitals are filled according to Hund’s Rule. They continue to pair up.
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
COPPER
One would expect the configuration of chromium atoms to end in 4s2 3d9.
To achieve a more stable arrangement of lower energy, one of the 4s electrons is promoted into the 3d.
1s2 2s2 2p6 3s2 3p6 4s1 3d10
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
ZINC
The electron goes into the 4s to restore its filled state and complete the 3d and 4s orbital filling.
1s2 2s2 2p6 3s2 3p6 4s2 3d10
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
GALLIUM - KRYPTON
The 4p orbitals are filled in exactly the same way as those in the 2p and 3p sub levels.
HUND’S RULEOF
MAXIMUM MULTIPLICITY
HUND’S RULEOF
MAXIMUM MULTIPLICITY
1 1s
22s
2p
4s
3
3s
3p
3d
44p
4d
4f
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STHE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS THE ELECTRONIC CONFIGURATIONS OF THE FIRST 36 ELEMENTS
GALLIUM - KRYPTON
Ga - 4p1
Ge - 4p2
As - 4p3
Se - 4p4
Br - 4p5
Kr - 4p6
Remember that the 4p configurations follow Hund’s Rule with the electrons remaining unpaired to give more stability.
Prefix with…
1s2 2s2 2p6 3s2 3p6 4s2 3d10
1s1
1s2
1s2 2s1
1s2 2s2
1s2 2s2 2p1
1s2 2s2 2p2
1s2 2s2 2p3
1s2 2s2 2p4
1s2 2s2 2p5
1s2 2s2 2p6
1s2 2s2 2p6 3s1
1s2 2s2 2p6 3s2
1s2 2s2 2p6 3s2 3p1
1s2 2s2 2p6 3s2 3p2 1s2 2s2 2p6 3s2 3p3 1s2 2s2 2p6 3s2 3p4
1s2 2s2 2p6 3s2 3p5
1s2 2s2 2p6 3s2 3p6
1s2 2s2 2p6 3s2 3p6 4s1
1s2 2s2 2p6 3s2 3p6 4s2 1s2 2s2 2p6 3s2 3p6 4s2 3d1
1s2 2s2 2p6 3s2 3p6 4s2 3d2
1s2 2s2 2p6 3s2 3p6 4s2 3d3
1s2 2s2 2p6 3s2 3p6 4s1 3d5
1s2 2s2 2p6 3s2 3p6 4s2 3d5
1s2 2s2 2p6 3s2 3p6 4s2 3d6
1s2 2s2 2p6 3s2 3p6 4s2 3d7
1s2 2s2 2p6 3s2 3p6 4s2 3d8
1s2 2s2 2p6 3s2 3p6 4s1 3d10
1s2 2s2 2p6 3s2 3p6 4s2 3d10
H
He
Li
Be
B
C
N
O
F
Ne
Na
Mg
Al
Si
P
S
Cl
Ar
K
Ca
Sc
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
ELECTRONIC CONFIGURATIONS OF ELEMENTS 1-30
ELECTRONIC CONFIGURATION OF IONSELECTRONIC CONFIGURATION OF IONS
• 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 (EXC. transition metals)
SODIUM Na 1s2 2s2 2p6 3s1 1 electron removed from the 3s orbital
Na+ 1s2 2s2 2p6
CHLORINE Cl 1s2 2s2 2p6 3s2 3p5 1 electron added to the 3p orbital
Cl¯ 1s2 2s2 2p6 3s2 3p6
ELECTRONIC CONFIGURATION OF IONSELECTRONIC CONFIGURATION OF IONS
• 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 (EXC. transition metals)
SODIUM Na 1s2 2s2 2p6 3s1 1 electron removed from the 3s orbital
Na+ 1s2 2s2 2p6
CHLORINE Cl 1s2 2s2 2p6 3s2 3p5 1 electron added to the 3p orbital
Cl¯ 1s2 2s2 2p6 3s2 3p6
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
How is electronic configuration related to the structure of the Periodic Table?
Key Definitions• Atomic Orbital = a region in an atom that can
hold up to 2 electrons with opposite spins
• Principal quantum number, n = a number representing the overall energy of each orbital (increases with distance from the nucleus)
• A Shell or Energy Level = a group of atomic orbitals with the same quantum number, n.
• Electronic Configuration = the arrangement of electrons in an atom
Principal quantum number
electron
Atomic orbital
Sub-shells (for the n=2 shell)
The n=2 Shell
Put arrows on to these
labels
Principal quantum number
electron
Atomic orbital
Sub-shells (for the n=2 shell)
The n=2 Shell
AS Chemistry Unit F321 Module 1.2.1 Electron Structure
Electron StructureDefinitions & Examples
Orbital Shell Principal Quantum Number
Sub-shell
Electron Configuration
AS Chemistry Unit F321 Module 1.2.1 Electron Structure
Ionisation Energy
First Ionisation Energy
Successive IonisationEnergies
Afffected by:
Definition, Examples
Definition, Examples
What they can be used to prove, graphs to show them, explanations:
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Unit F321
Module 1.2.1Electron Structure
Define the terms first ionisation energy and successive ionisation energy;
Explain that ionisation energies are influenced by nuclear charge, electron shielding and the distance of the outermost electron from the nucleus;
predict from successive ionisation energies of an element: (i) the number of electrons in each shell of an atom, (ii) the group of the element;
state the number of electrons that can fill the first four shells;
describe an orbital as a region that can hold up to two electrons, with opposite spins;
describe the shapes of s and p orbitals;
state the number of: (i) orbitals making up s-, p- and d-sub- shells, (ii) electrons that occupy s-, p- and d-sub- shells;
describe the relative energies of s-, p- and d- orbitals for the shells 1, 2, 3 and the 4s and 4p orbitals;
deduce the electron configurations of: (i) atoms, given the atomic number, up to Z = 36, (ii) ions, given the atomic number and ionic charge, limited to s and p blocks up to Z = 36;
classify the elements into s, p and d blocks.
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