Transcript Lecture 1.6 PowerPoint

Catalyst
1.
2.
3.
Ways to Organize Shapes
• Organize a sphere on xyz coordinate plane
• Organize dumb bells on xyz coordinate plane
Today’s Learning Targets
• 1.6 – I can characterize an electron based on its 4
quantum numbers (n, l, ml, and ms). I can explain
what each of these numbers indicate and discuss
the importance of these numbers.
• 1.7 – I can describe the shape, number, and energy
level of the s, p, d, and f orbitals. Furthermore, I can
draw the s and p orbitals.
• 1.8 – I can write the electron configuration and
orbital diagram for any element on the Periodic
Table using the Pauli Exclusion Principle and Hund’s
Rule.
Orbitals
• The solution to the Schrödinger equation gives us
orbitals for a particular element.
• Every orbital has a special shape and energy level.
• We keep the idea of energy level (n = 1,2,3, etc.)
from the Bohr model, but remove idea of fixed
orbits.
• There are 4 characteristic shapes that an orbital
can take.
s Orbitals
• Spherical shape
• Only one possible orientation around the nucleus.
• Seen whenever n (energy level) is 1 or greater
All s orbitals have
only one possible
orientation.
p Orbitals
• All p-orbitals are dumb-bell shaped.
• Because of the unique shape there are 3 possible
orientations around the nucleus (one along each of
the 3 axis).
• Seen whenever n is 2 or greater
d Orbitals
• All d orbitals have a four-leaf clover shape.
• 4 possible orientations within the plane and one
odd shape (dz2)
• Appear when n is 3 or higher.
f Orbitals
• These orbitals appear whenever n is 4 or higher
• Only seen in elements that have many electrons.
Quick Talk
• 1 partner explain s and d orbitals. 1 partner explain
p and f orbitals. Be able to draw s and p orbital
Quantum Numbers
• We can describe any orbital that an electron exists
in using 4 quantum numbers.
• No 2 orbitals can have the same 4 quantum
numbers.
• Quantum Numbers:
1. Principal Quantum Number (n)
2. Angular Momentum Quantum Number (l)
3. Magnetic Quantum Number (ml)
4. Spin Magnetic Quantum Number (ms)
Principal Quantum Number (n)
• Describes the energy level of the orbital
• Can have any integer value of 1 or greater (1, 2, 3,
etc.)
• The bigger n becomes, the higher the energy level
Angular Momentum ( )
• Describes the shape of our orbital (s, p, d, or f)
• Can have any value from 0 to (n – 1)
• Each orbital has an assigned angular momentum:
Value of
Letter used
0
s
1
p
2
d
3
f
Quick Write
• If I have an element at the n = 3 energy level, then
what type(s) of orbitals do I have?
Magnetic Quantum Number (m
)
• ml is any number – to +
• Every orbital can take on a certain number of
“allowed” orientations.
• Tells you the number of total electrons an orbital
can hold
• The number of allowed orientations is the sum of –
to +
Quick Write
• How many allowed orientations are there for the s
orbital ( =0)? How many electrons can it hold?
• How many allowed orientations are there for the d
orbital ( =2)? How many electrons can it hold?
Spin Magnetic Quantum
Number (ms)
• Any orbital can contain, at most, 2 electrons
• If electrons are in the same orbital, then they must
have opposite spins or ms values
• An electron can either have a spin of +½ or -½
Summarize
Around the World
• Around the room there are 10 problems. Cycle
through the problems to practice writing electron
configurations.
• Complete all problems
5 Minute Break
Who would perform at
the ultimate concert?
Concert of a Lifetime
Concert of a Lifetime
Stage
Orbitals and their Energy
• Orbitals, based on many
different reasons, have
varying energies.
• n does not determine
energy levels when
comparing orbitals
Electron
Configurations
• Electron configurations
describe the distribution of
each electron among the
various orbitals in the atom
Pauli Exclusion Principle
• Within an atom, no two electrons can have the
same set of 4 quantum numbers.
Orbital energy
diagrams
Aufbau principle: Build
up each atom from the
preceding atom by
“filling” electrons in from
the bottom.
Hund’s Rule
• When placing electrons into a group of similar
orbitals, electrons enter empty orbitals first before
they form pairs
Class Example
• Draw the electron configuration for fluorine.
Table Talk
• Draw the electron configuration for magnesium
3 Essential Principles
1. Pauli Exclusion Principle – Every electron gets its own
unique quantum number per element.
2. Hund’s Rule – Electrons spread out within the same
energy level.
3. Aufbau Principle – Fill the lowest energy orbital first
How to Remember Order of
Orbital Filling
1s
2s
3s
4s
5s
6s
2p
3p 3d
4p 4d 4f
5p 5d 5f
6p 6d 6f
Periodic Table Quantum
Shortcut!
• The position of the element determines the last
orbital and energy level filled.
Condensed Electron
Configurations
• Abbreviate configurations using Noble Gases.
• Choose the Noble Gas in the row just above the
element of interest.
• Substitute this Noble Gas for all electrons prior to the
row the element is in.
10 electrons = Neon!
1s22s22p63s23p4
[Ne]3s23p4
Class Example
• Write the electron configuration for zinc using
condensed notation
Table Talk
• Write the electron configuration for Tin.
JTPS: Analyze the Configuration
• Which configuration for chromium is more stable. WHY?:
1s22s22p63s23p64s23d4
or
1s22s22p63s23p64s13d5
Strange Electron Configurations
• Due to the closeness in energy of the 3d and 4s
orbitals, electrons will spread out in order to satisfy
Hund’s Rule.
• Seen most often in chromium and copper.
Summarize
Coach and Correct
Question 1
• In 3 words or less for each:
o Describe the Pauli Exclusion Principle
o Describe Hund’s Rule
o Describe the Aufbau Principle
Question 2
• What is the principal quantum number, number of
electrons, and angular momentum of 5p6
Question 3
• Write the long-form electron configuration for sulfur
Question 4
• Write the condensed electron configuration for
titanium
Question 5
• Why do electrons fill the lowest energy level first?
Question 6
• Looking at the following electron configurations,
which represents a chemically unreactive element?
Justify your answer!
a) 1s____2s ↑ _
b) 1s ↑↓ 2s ↑↓_
c) 1s ↑↓ 2s ↑↓ 2p ↑
↑ ____
d) 1s ↑↓ 2s ↑↓ 2p ↑↓_ ↑↓ _↑↓_
e) [Ar]4s ↑↓ 3d ↑↓
↑
↑
↑
↑_
Question 7
• The contour representation of one of the orbitals for
the n = 3 shell of hydrogen atom is shown below
a) What is the quantum number l for this orbital?
b) What is the notation for this orbital
Question 8
• An element has a valence shell configuration of
ns2np5, what element(s) is it?
Question 9
• You friend writes the electron configuration for
phosphorus as: [He]3s23p3. What is wrong with the
way that they wrote the configuration?
Question 10
• Write the condensed electron configuration for
uranium
Closing Time
• You should have all Chapter 6 reading and
homework problems done by Monday/Tuesday to
be on track.
• Also, read corresponding chapter in Cracking the
AP Chemistry Exam
• Pre-lab for Lab 2 due at start of class
Monday/Tuesday.
• No pre-lab = you cannot start lab on time = staying
after school to finish the lab.