Orbital Notation and

Electron Configuration

Orbital Notation and

Electron Configuration

October 20thOctober 20th

Distance From The NucleusDistance From The Nucleus

Called the Principle Quantum Number (n)

Describes the principle energy leveln = 1, 2, 3

Called the Principle Quantum Number (n)

Describes the principle energy leveln = 1, 2, 3

Shape of the OrbitalShape of the Orbital

Described by Orbital quantum number (l)

Tells you the shape of the orbital the electron is in

Is it an s, p, d, or f orbital?

Described by Orbital quantum number (l)

Tells you the shape of the orbital the electron is in

Is it an s, p, d, or f orbital?

Position in 3D SpaceDescribed by Magnetic Quantum Number (m)Indicated the position of the orbital around the 3

axes (x, y, z)

Electron’s Spin

The direction of the electron’s spin is described by the spin quantum number

Electrons can be either up or downWhen electrons are part of a pair, they

must spin in opposite directions

Pauli Exclusion PrinciplePauli Exclusion PrincipleNo two electrons in the same atom can

have the same four quantum numbers (the same description)

No two electrons can have the same address

Electrons are repulsed by each other, so they cannot live together… Hence makes sense they have opposite spins!

No two electrons in the same atom can have the same four quantum numbers (the same description)

No two electrons can have the same address

Electrons are repulsed by each other, so they cannot live together… Hence makes sense they have opposite spins!

Review Of Energy LevelsReview Of Energy Levels

n = 1s orbital (2 electrons)

n = 2s orbital (2 electrons)p orbital (6 electrons)

n = 3s orbital (2 electrons)p orbital (6 electrons)d orbital (10 electrons)

n = 4s orbital (2 electrons)p orbital (6 electrons)d orbital (10 electrons)f orbital (14 electrons)

n = 1s orbital (2 electrons)

n = 2s orbital (2 electrons)p orbital (6 electrons)

n = 3s orbital (2 electrons)p orbital (6 electrons)d orbital (10 electrons)

n = 4s orbital (2 electrons)p orbital (6 electrons)d orbital (10 electrons)f orbital (14 electrons)

3 Rules for Electron Configuration3 Rules for Electron Configuration

1) Aufbau Principle - electrons occupy the orbitals of lowest energy first

2) Pauli Exclusion Principle - no two electrons can have the same address(same 4 quantum #s)

3) Hund’s Rule - Electrons try to occupy different orbitals before pairing up

1) Aufbau Principle - electrons occupy the orbitals of lowest energy first

2) Pauli Exclusion Principle - no two electrons can have the same address(same 4 quantum #s)

3) Hund’s Rule - Electrons try to occupy different orbitals before pairing up

Orbital Notation

order in which electrons are filled

Orbital Notation

order in which electrons are filled

The Order in which orbitals fill…The Order in which orbitals fill…

Orbital NotationOrbital Notation

Arrowsdepictelectronspin

ORBITAL BOX NOTATIONfor He, atomic number = 2

1s

21 s

Arrowsdepictelectronspin

ORBITAL BOX NOTATIONfor He, atomic number = 2

1s

21 s

Arrangement of Arrangement of Electrons in AtomsElectrons in AtomsArrangement of Arrangement of Electrons in AtomsElectrons in Atoms

Each orbital can be assigned no more than 2 Each orbital can be assigned no more than 2 electrons!electrons!

Each orbital can hold a pair of electrons per Each orbital can hold a pair of electrons per orientationorientationss 1 orientation(pair)1 orientation(pair) 2 electrons 2 electrons pp 3 orientations3 orientations 6 electrons 6 electronsdd 5 orientations5 orientations 10 electrons 10 electronsff 7 orientations7 orientations 14 electrons 14 electrons

Each orbital can be assigned no more than 2 Each orbital can be assigned no more than 2 electrons!electrons!

Each orbital can hold a pair of electrons per Each orbital can hold a pair of electrons per orientationorientationss 1 orientation(pair)1 orientation(pair) 2 electrons 2 electrons pp 3 orientations3 orientations 6 electrons 6 electronsdd 5 orientations5 orientations 10 electrons 10 electronsff 7 orientations7 orientations 14 electrons 14 electrons

Orbital Diagram

_____ 1s

_____ _____ _____ _____ 2s 2px 2py 2pz

_____ _____ _____ _____ _____ _____ _____ _____ _____ 3s 3px 3py 3pz 3d

_____ _____ _____ _____ _____ _____ _____ _____ _____ 4s 4px 4py 4pz 4d

_____ _____ _____ _____ _____ _____ _____ _____ _____ 5s 5px 5py 5pz 5d

_____ 6s

How Orbitals Fill….How Orbitals Fill….

_____ 1s

_____ _____ _____ _____ 2s 2px 2py 2pz

_____ _____ _____ _____ 3s 3px 3py 3pz

Electron Configuration – StrontiumElectron Configuration – Strontium

_____ 1s

_____ _____ _____ _____ 2s 2px 2py 2pz

_____ _____ _____ _____ _____ _____ _____ _____ _____ 3s 3px 3py 3pz 3d

_____ _____ _____ _____ _____ _____ _____ _____ _____ 4s 4px 4py 4pz 4d

_____ _____ _____ _____ _____ _____ _____ _____ _____ 5s 5px 5py 5pz 5d

_____ 6s

Valence electrons are electrons in the outermost energy level of an atom.

_____ 1s

_____ _____ _____ _____ 2s 2px 2py 2pz

_____ _____ _____ _____ 3s 3px 3py 3pz

Valence electrons

Example: Sulfur

Practice on your own!Practice on your own!Draw the orbital diagram for Calcium

Draw the orbital diagram for Silicon

Draw the orbital diagram for Calcium

Draw the orbital diagram for Silicon

Electron ConfigurationElectron Configuration

11 s

Energy LevelSubshell(s, p, d, f)

no. of

electrons

for H, atomic number = 1

Electron ConfigurationElectron ConfigurationFortunately! Its like orbital diagrams but

without drawing the orbitals…

Fill electrons into lower energy levels firstFollow order of fillingRemember how many electrons each level can

hold: s holds 2, p holds 6, d 10, f 14

Fortunately! Its like orbital diagrams but without drawing the orbitals…

Fill electrons into lower energy levels firstFollow order of fillingRemember how many electrons each level can

hold: s holds 2, p holds 6, d 10, f 14

ExamplesExamplesHelium: 1s2

Boron : 1s22s22p1

Magnesium: 1s22s22p63s2

Bromine: 1s22s22p63s23p64s23d104p5

Helium: 1s2

Boron : 1s22s22p1

Magnesium: 1s22s22p63s2

Bromine: 1s22s22p63s23p64s23d104p5

1s1

1s22s22p63s1

1s22s22p63s2

1s22s22p63s23p5

1s22s22p63s23p6

1s22s22p63s23p64s23d104p3

Practice on your own!

Hydrogen

Sodium

Magnesium

Chlorine

Argon

Arsenic

Octet rule - all elements want to have a full set of valence electrons

Atoms will lose or gain electrons in trying to achieve a full octet

Octet rule - all elements want to have a full set of valence electrons

Atoms will lose or gain electrons in trying to achieve a full octet

Octet Rule

Octet Rule states that atoms will gain or lose electrons to achieve a full outermost energy level.

This is usually 8 electrons (s2 p6).

Example: Oxygen

_____ 1s

_____ _____ _____ _____ 2s 2px 2py 2pz

O

Octet Rule