Objectives SWBAT distinguish among the Aufbau principle, the Pauli exclusion principle, and Hund’s...
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Objectives SWBAT distinguish among the Aufbau principle, the Pauli exclusion principle, and Hund’s rule. SWBAT write electron configurations for selected
Objectives SWBAT distinguish among the Aufbau principle, the
Pauli exclusion principle, and Hunds rule. SWBAT write electron
configurations for selected elements.
Slide 2
Electron Configuration for Neutral Atoms
Slide 3
Electron Cloud A region surrounding the nucleus with the
highest probability of finding electrons Electron Cloud
Nucleus
Slide 4
Principal Quantum Number: (main energy level) Certain regions
within the electron cloud where electrons are found. Main energy
levels range from 1 to 7 based on the distance from the nucleus.
The higher the number, the further from the nucleus. 1 2 3 4 5 6
7
Slide 5
Sublevels in main energy levels Describes the shape of the
orbital that an electron occupies Labeled s,p,d,f according to
shape As you move further from the nucleus (higher energy level),
more electrons can be in an energy levelso the # of sublevels
increases
Slide 6
Orbital Shape 3D region around the nucleus There are different
orbitals for the orientations around the nucleus Each orbital can
hold 2 electrons but they must have opposite spins
Slide 7
s orbital - sphere
Slide 8
p orbital peanut/propeller
Slide 9
d orbital desk fan f orbital flower
Slide 10
Principal quantum number: main en level (n) Sublevels In main
en. level (n sublevels) # of orbitals per sublevel # of electrons
per sublevel # of e- per main en level (2n 2 ) 1s122 2spsp 1313
2626 8 3spdspd 135135 2 6 10 18 4spdfspdf 1 3 5 7 2 6 10 14 32
Slide 11
Review Where are electrons located in an atom? In the electron
cloud a region surrounding the nucleus with the highest probability
of finding electrons Where are electrons within the electron cloud?
In certain regions called Energy Levels (n=1,2,3,4,5,6,7), based on
the distance from the nucleus Where are electrons within an Energy
Level? In Sublevels, which have specific shapes (ex. s, p, d, f)
Where are electrons within a Sublevel? In orbitals! But only 2
electrons per orbital.
Slide 12
Electron Configuration Tells us where electrons are in an atom
for a neutral atom Shows what energy level, sublevel, and
orbital
Slide 13
Electron Configuration Numbers and letters used to represent
orbitals with the raised number showing electrons H: 1s 1 1 st
energy level, s sublevel, 1 e - Energy Levelsublevel # of
electrons
Slide 14
3 Rules for Electron Arrangement Aufbau Principle Electrons
always start filling at the lowest energy level. Within each energy
level, the s sublevel fills first, then p, then d, then f.
Slide 15
3 Rules for Electron Arrangement Pauli Exclusion Principle A
maximum of 2 electrons can be in one orbital. They must have
opposite spins.
Slide 16
3 Rules for Electron Arrangement Hunds Rule Electrons fill each
orbital in a sublevel before they start pairing up. p orbitals
Slide 17
3 Ways to Represent Electron Configurations 1.Orbital Notation
(diagram) 2.Electron-configuration Notation 3.Noble Gas
Notation
Slide 18
Orbital Diagram 1s 2s 2p x 2p y 2p z Neutral atom of Oxygen 8
protons = 8 electrons
Slide 19
Electron Configuration Notation The electron configuration for
oxygen. Eliminate lines and arrows of orbital diagram 1s 2 2s 2 2p
4
Slide 20
4s is filled before 3d because the 4s sublevel has a lower
energy then the 3d sublevel
Slide 21
Drill: pd 310/29/14 Write the electron configurations for the
following elements: P, Ar, and Br.
Objectives SWBAT distinguish among the Aufbau principle, the
Pauli exclusion principle, and Hunds rule. SWBAT write electron
configurations for selected elements.
Slide 24
Noble Gas Notation Shorthand e - configuration e -
configurations of noble gases can be written using bracketed
symbols ex: Ne 1s 2 2s 2 2p 6 = [Ne] Write the bracketed symbol for
the noble gas that precedes the element (period above it) and then
continue filling orbitals with remaining electrons.
Slide 25
Slide 26
Drill 10/30, 31/14 What are the rows on the periodic table
called? What about the columns?
Slide 27
Periodic Table The rows on the periodic table are called
periods. How many periods are there? 7 The columns on the periodic
table are called families or groups. How many groups are there?
18
Slide 28
Valence electrons Valence electrons = # of e- in outermost
orbital (highest main en level). These are the electrons that
determine chemical properties of each element
Slide 29
Take out your periodic table We are going to look at the
relationship between how the periodic table is organized and
electron configuration.
Slide 30
S, p,d, and f-block elements The odd shape of the periodic
table becomes clear if we divide it into sections based on an atoms
energy sublevel being filled with valence electrons. Sublevels =
spdf!
Slide 31
Slide 32
Mark these sublevels on your periodic table.
Slide 33
What is the relationship between the maximum number of
electrons an energy sublevel can hold and the size of that
block?
Slide 34
The number of columns in the block is equal to the maximum
number of electrons the energy sublevel can hold. s = 2p = 6 d = 10
f = 14
Slide 35
Valence Electrons across periods For s and p sublevels only!
Across increase Na Mg Al Si Ar 3s 1 3s 2 3s 2 3p 1 3s 2 3p 2 3s 2
3p 6 1 2 3 4... 8
Slide 36
Valence Electrons and groups For s and p sublevels only! This
is one of the most important relationships in chem. Atoms in the
same group have similar chemical properties because they have the
same number of valence electrons.Down the column stays the same.
This is one of the most important relationships in chem. Atoms in
the same group have similar chemical properties because they have
the same number of valence electrons. Be Mg Ca Sr 2s 2 3s 2 4s 2 5s
2 2 2 2 2
Slide 37
Valence electrons & Period The main energy level of an
elements valence electrons indicates the period on the periodic
table in which it is found. For. Ex. Li valence electron is in the
second main energy level and is found in period 2.
Slide 38
Quantum Numbers Activity
Slide 39
Quantum Numbers Quantum numbers specify the properties of the
atomic orbitals, and the properties of electrons in orbitals. Based
on Schrodingers equation. If electron configuration is an e-s
address, quantum numbers would be its latitude and longitude.
Slide 40
Principal Quantum Number Angular Momentum Quantum Number
Magnetic Quantum Number Spin Quantum Number Take out of piece of
paper. Fold it twice to form sections for the headers below. Write
the headers in each section.
Slide 41
Record for each Quantum # Definition Symbol The allowed values
An example You will need a textbook to look up information about
the quantum numbers. Pg. 101.
Slide 42
Quantum Number Review Notes
Slide 43
Quantum Numbers Used to describe various properties of the
orbitals Each electron is assigned a set of four quantum numbers
which, in order, are n, l, m l, and m s Its like giving each
electron its own latitude and longitude
Slide 44
Principle quantum number Definition: indicates the main energy
level occupied by the electron Symbol: n Values: (written as
integers) 1,2,3,4,5,6,7
Slide 45
Angular Momentum Quantum Numbers Definition: indicates the
shape of the orbital Symbol: l Values: 0 = s 1 = p 2 = d 3 = f For
a specific energy level, the number of orbital shapes (sublevels)
available is equal to n. The values of l are equal to n-1.
Slide 46
Magnetic Quantum Numbers Definition: represents the orientation
of an orbital around the nucleus Symbol: m l Values: for a
p-orbital -1, 0, 1 The number of different possible values for m l
determine the number of orbitals in a sublevel.
Slide 47
Spin Quantum Numbers Definition: represents the spin states of
electrons in an orbital Symbol: m s Values: +1/2, -
Slide 48
Slide 49
Mark these on your periodic table.
Slide 50
Can an e- be described by the following set of quantum numbers?
n=2, l=1, m l = -1 All quantum numbers are allowed values
Slide 51
Can an e- be described by the following set of quantum numbers?
n=1, l=1, m l = +1 Not possible. The value of l must be less than
the value of n.
Slide 52
Can an e- be described by the following set of quantum numbers?
n=7, l=3, m l = +3 All the quantum numbers are allowed values.
Slide 53
Can an e- be described by the following set of quantum numbers?
n=3, l=1, m l =-3 Not possible. The value of m l must be in the
range -l to +l
Slide 54
Writing Quantum Numbers You can identify the quantum numbers
for any electron in an element Start by writing out the the
electron configuration and orbital diagram for the element Locate
the electron in the orbital diagram that you are solving the
quantum number for Determine the 4 quantum numbers
Slide 55
Hydrogens electron Write electron configuration Draw orbital
diagram n= 1 l= 0 m l = 0 m s = +1/2
Slide 56
Heliums second electron Write electron configuration Draw
orbital diagram n= 1 l= 0 m l = 0 m s = -1/2
Slide 57
Lithiums third electron Write electron configuration Draw
orbital diagram n= 2 l= 0 m l = 0 m s = +1/2
Slide 58
Oxygens fourth electron Write electron configuration Draw
orbital diagram n= 2 l= 0 m l = 0 m s = -1/2
Slide 59
Flourines 6 th electron Write electron configuration Draw
orbital diagram n= 2 l= 1 m l = 0 m s = +1/2