4.05 Atomic Structure and Electronic Configuration Aug ‘171
4.05 Atomic Structure and Electronic Configuration
Dr. F. O. GarcesChemistry 100Miramar College
Learning Objectives/Terminology-AufbauHund’s RulePauli Exclusion PrincipleDiamagnetism/ParamagnetismNe-Va-S-P
Arranging the electrons in an atom
4.05 Atomic Structure and Electronic Configuration Aug ‘172
Electronic ConfigurationHow are the electrons of an atom arranged in the atom?
What are shells and orbitals arrange outside the nuclei of an atom?
How is the e- arrangement liken to that of a Hotel room (Hotel del Orbital) ?
What is the importance of the valence electrons and how do these influence chemistry?
4.05 Atomic Structure and Electronic Configuration Aug ‘173
Prelude to eConfigurationPlacing electrons in orbitals to complete the electron configuration.
4.05 Atomic Structure and Electronic Configuration Aug ‘174
Shells and Orbitals
4.05 Atomic Structure and Electronic Configuration Aug ‘175
Relative Energies for Shells and Orbitals
1
2
3
4
567∞8
s p d f
Relative Energies of the orbitals
4.05 Atomic Structure and Electronic Configuration Aug ‘176
Hotel del Orbitals
s p d f
1
2
3
4
Filling Order (Aufbau Principle)
Like the hotel del Orbital, the shells of an atom are staggered and are filled based on their relative energies
4.05 Atomic Structure and Electronic Configuration Aug ‘177
Hotel del Orbitals and a pictorial view of the shell arrangements
The filling order can be memorized by the following scheme
1
2
3
4
4.05 Atomic Structure and Electronic Configuration Aug ‘178
2s• H = 1s1
• He = 1s2
• Li = 1s2 2s1
• Be = 1s2 2s2
• B = 1s2 2s2 2p1
• C = 1s2 2s2 2p2
• N = 1s2 2s2 2p3
• O = 1s2 2s2 2p4
• F = 1s2 2s2 2p5
• Ne = 1s2 2s2 2p6
1s
The First 10 elements:
2p
+ +
4.05 Atomic Structure and Electronic Configuration Aug ‘179
Electron ConfigurationHydrogen and Helium
H
HeHe = 1s2
H = 1s1
1s 2s 2p
1s 2s 2p
Pauli Exclusion Principle
4.05 Atomic Structure and Electronic Configuration Aug ‘1710
Relative Energies for Shells and Orbitals
1
2
3
4
567∞8
s p d f
Relative Energies of the orbitals
4.05 Atomic Structure and Electronic Configuration Aug ‘1711
Electron Configuration:Lithium to Beryllium
Be
+ +
=
Li+ +
=
Li = 1s2 2s1
Be = 1s2 2s21s 2s 2p
1s 2s 2p
Aufbau Process
4.05 Atomic Structure and Electronic Configuration Aug ‘1712
Relative Energies for Shells and Orbitals
1
2
3
4
567∞8
s p d f
Relative Energies of the orbitals
4.05 Atomic Structure and Electronic Configuration Aug ‘1713
Electron Configuration: Boron to Nitrogen
N
+ +
=
C
+ +
=
B
+ +
=
B = 1s2 2s2 2p1
N = 1s2 2s2 2p3
1s 2s 2p
1s 2s 2p
1s 2s 2p
C = 1s2 2s2 2p2 Hund’s Rule
Paramagnetic
4.05 Atomic Structure and Electronic Configuration Aug ‘1714
Relative Energies for Shells and Orbitals
1
2
3
4
567∞8
s p d f
Relative Energies of the orbitals
4.05 Atomic Structure and Electronic Configuration Aug ‘1715
Electron Config: Oxygen to Neon
O
+ +
=
F
+ +
=
Ne
+ +
=
F = 1s2 2s2 2p5
Ne = 1s2 2s2 2p6
1s 2s 2p
1s 2s 2p
1s 2s 2p
O = 1s2 2s2 2p4
Diamagnetic
4.05 Atomic Structure and Electronic Configuration Aug ‘1716
Relative Energies for Shells and Orbitals
1
2
3
4
567∞8
s p d f
Relative Energies of the orbitals
4.05 Atomic Structure and Electronic Configuration Aug ‘1717
Electron Configuration using the Periodic Table
When using the Periodic table to determine the electron
configuration of an atom, it is important to understand the
layout of the periodic table.
The row of a periodic table can be used to determine which
energy level, 1, 2, 3... the valence electrons are located. The
column of the periodic table helps determine how many valence
electron an atom possesses. Elements in the 1A column (family)
have one valence electron, in the IIA column, elements have two
valence electron, in the IIIA family, elements have three
valence electrons, and so on.
4.05 Atomic Structure and Electronic Configuration Aug ‘1718
The elements designated in -block is where the very last electrons are found in the s-orbitals. Therefore the elements in portion of the periodic table is referred to as the s-block elements.
The elements designated in -block is where the very last electrons are found in the p-orbitals. The elements found in this portion of the periodic table is referred to as the p-block elements.
The same can be said about the -block and -block with the elements found in this portion of the periodic table referred to as the d-block (transition metals) and f-block (man-made) elements.
Electron Configuration using the Periodic Table
4.05 Atomic Structure and Electronic Configuration Aug ‘1719
Electron Configuration: ne-va-s-p
e- config. for Sulfur ?
1IA
18VIIIA
1 2IIA
13IIIA
14IVA
15VA
16VIA
17VIIA
2
3 3IIIB
4IVB
5VB
6VIB
7VIIB
8 9VIIIB
10 11IB
12IIB
4
5
6
7
H1s1
Li2s1Na3s1
K4s1
Rb5s1
Cs6s1
Fr7s1
Be2s2
Mg3s2
Ca4s2
Sr5s2
Ba6s2
Ra7s2
Sc3d1
Ti3d2
V3d3
Cr4s13d5
Mn3d5
Fe3d6
Co3d7
Ni3d8
Zn3d10
Cu4s13d10
B2p1
C2p2
N2p3
O2p4
F2p5
Ne2p6
He1s2
Al3p1
Ga4p1
In5p1
Tl6p1
Si3p2
Ge4p2
Sn5p2
Pb6p2
P3p3
As4p3
Sb5p3
Bi6p3
S3p4
Se4p4
Te5p4
Po6p4
Cl3p5
Be4p5
I5p5
At6p5
Ar3p6
Kr4p6
Xe5p6
Rn6p6
Y4d1
La5d1
Ac6d1
Cd4d10
Hg5d10
Ag5s14d10
Au6s15d10
Zr4d2
Hf5d2
Db6d2
Nb4d3
Ta5d3
Jl6d3
Mo5s14d5
W6s15d5
Rf7s16d5
Tc4d5
Re5d5
Bh6d5
Ru4d6
Os5d6
Hn6d6
Rh4d7
Ir5d7
Mt6d7
Ni4d8
Ni5d8
• ne - number of electrons; the total number of electrons• va - valence electrons; the number of valence electrons• s - shell of valence electrons• p - previous noble gas
4.05 Atomic Structure and Electronic Configuration Aug ‘1720
Electron Configuration: Sulfur
p - previous noble gas = Ne (10 e-)
ne - number of electrons; the total number of electrons; this equals the number of protons or atomic number = 16
Va - valence electrons; the number of valence electrons = 6
s - shell of valence electrons = 3
1IA
18VIIIA
1 2IIA
13IIIA
14IVA
15VA
16VIA
17VIIA
2
3 3IIIB
4IVB
5VB
6VIB
7VIIB
8 9VIIIB
10 11IB
12IIB
4
5
6
7
H1s1
Li2s1
Na3s1
K4s1
Rb5s1
Cs6s1
Fr7s1
Be2s2
Mg3s2
Ca4s2
Sr5s2
Ba6s2
Ra7s2
Sc3d1
Ti3d2
V3d3
Cr4s13d5
Mn3d5
Fe3d6
Co3d7
Ni3d8
Zn3d10
Cu4s13d10
B2p1
C2p2
N2p3
O2p4
F2p5
Ne2p6
He1s2
Al3p1
Ga4p1
In5p1
Tl6p1
Si3p2
Ge4p2
Sn5p2
Pb6p2
P3p3
As4p3
Sb5p3
Bi6p3
S3p4
Se4p4
Te5p4
Po6p4
Cl3p5
Be4p5
I5p5
At6p5
Ar3p6
Kr4p6
Xe5p6
Rn6p6
Y4d1
La5d1
Ac6d1
Cd4d10
Hg5d10
Ag5s14d10
Au6s15d10
Zr4d2
Hf5d2
Db6d2
Nb4d3
Ta5d3
Jl6d3
Mo5s14d5
W6s15d5
Rf7s16d5
Tc4d5
Re5d5
Bh6d5
Ru4d6
Os5d6
Hn6d6
Rh4d7
Ir5d7
Mt6d7
Ni4d8
Ni5d8
S
Ne
e- config for SulfurS = [Ne]3s23p4
• ne - number of electrons; the total number of electrons• va - valence electrons; the number of valence electrons• s - shell of valence electrons• p - previous noble gas
4.05 Atomic Structure and Electronic Configuration Aug ‘1721
1
2
3
4
567∞8
Relative Energies of the orbitals and the filling order.
Electron arrangement for the Sulfur atom
The 16 electrons for sulfur occupy the shells & orbitals of sulfur from the lowest energy to the highest.
s p d f
S
16 total electrons
e- config for SulfurS = [Ne] 3s2 3p4
4.05 Atomic Structure and Electronic Configuration Aug ‘1722
1
2
3
4
567∞8
Relative Energies of the orbitals and the filling order.
Electron arrangement for the Scandium atom
The 16 electrons for sulfur occupy the shells & orbitals of sulfur from the lowest energy to the highest.
s p d f
21 total electrons
e- config for ScandiumSc = [Ar]4s23d1
Sc
4.05 Atomic Structure and Electronic Configuration Aug ‘1723
1
2
3
4
567∞8
Relative Energies of the orbitals and the filling order.
Electron arrangement for the Scandium atom
The 16 electrons for sulfur occupy the shells & orbitals of sulfur from the lowest energy to the highest.
s p d f
Sn
50 total electrons
e- config for TinSn = [Kr]5s24d105p2
4.05 Atomic Structure and Electronic Configuration Aug ‘1724
The First 20 elements:
2s• H = 1s1
• He = 1s2
• Li = 1s2 2s1
• Be = 1s2 2s2
• B = 1s2 2s2 2p1
• C = 1s2 2s2 2p2
• N = 1s2 2s2 2p3
• O = 1s2 2s2 2p4
• F = 1s2 2s2 2p5
• Ne = 1s2 2s22p6
• Na = 1s2 2s22p63s1
• Mg = 1s2 2s22p63s2
• Al = 1s2 2s22p63s23p1
• Si = 1s2 2s22p63s23p2
• P = 1s2 2s22p63 s23p1
• S = 1s2 2s2 2p63s23p4
• Cl = 1s2 2s2 2p63s2 3p5
• Ar = 1s2 2s2 2p6 3s2 3p6
1s
2p
+ +
+ +
3p
3s
4.05 Atomic Structure and Electronic Configuration Aug ‘1725
Assignment:Determine the electron configuration.
1. Write out the electron configurations for the following atoms and ions. Determine the number of unpaired electrons in the ground state.
13Al 12Mg+250Sn 15P-3
34Se-132Ge+2
2. Write the electron box diagram for the following elements. Which have identical electron configuration (isoelectronic) ?
S-2 Cl Ar Ca+2
3. What does the term: Aufbau, Pauli Exclusion and Hund’s Rule mean?
4. How does atomic radius change as one goes left to right along the periodic table? Explain*.
5. How does the ionization change as one goes down the periodic table? Explain*.
* Explain, means explain why.