Download Tuesday Aug 19

Monday Oct 20
Objective: Write the electronic configuration of
any element.
Checkpoint:
• How many different photons of light can an
atom give off if it has 4 energy levels?
HW: Emission spectrum lab
(due Tuesday)
Electromagnetic Spectrum
Emission Spectroscopy Lab
Pre-lab questions:
1. According to the modern theory of the atom, where may an
atom’s electrons be found?
2. How do electrons become “excited”?
3. What form of energy emission accompanies the return of
excited electrons to the ground state?
4. Assume that an atom has a total of four possible energy
levels and that an electron can jump up or down between
any of these energy levels. Draw a model of these energy
levels, and use it to predict the maximum number of spectral
lines in the emission spectrum.
Emission Spectroscopy Lab
Data:
Sunlight/white light
Fluorescent light
Emission Spectroscopy Lab
Post-lab questions:
1. Compare the spectra produced by sunlight (white light)
and fluorescent sources. What are the similarities?
What are the differences?
2. Some elements have the same color, but brighter
spectral lines than others. How can the difference in
the brightness be explained?
3. Prior to its discovery on Earth, the existence of helium
was first confirmed in the sun. Explain how this can be
possible.
Erwin Schrödinger
• Quantum Mechanical Model
– Modern model
– Estimates the probability of finding an
electron within a certain volume of space
surrounding the nucleus
– Where you find the electron 90% of the
time
8
Energy Levels
• Principal quantum numbers (n) identify the
energy levels in an atom
– Tells you how far away the electron is from the
nucleus
– There are 1-7 energy levels, correlates with
period numbers
– Maximum number of 2n2 electrons per level
9
Atomic Orbitals
• Atomic orbitals are more specific regions
within each energy level where electrons
are found
– Highest probability of finding an electron
– designated by letters s,p,d,f
– Each orbital can hold 2 electrons
10
s, p, d, f orbitals
11
s, p, d, f orbitals
Electron Cloud Picture
13
Every atom has energy levels in which electrons
can be found.
Formula: 2n2 (where n = energy level)
Energy Level
Total # electrons
1
2
3
4
2
8
18
32
Each orbital can hold 2 electrons
Orbital Type
# of Orbitals
# of total
electrons
s-orbital
1
2
p-orbital
3
6
d-orbital
5
10
f-orbital
7
14
Writing Electron Configurations
Purpose: to summarize where the electrons are
(which energy level and orbital)
– Electron configuration notation (long form)
– Noble gas notation (short form)
– Orbital notation (picture form)
Write e-configs for:
Carbon
Magnesium
Arsenic
Gold