Warm Up
1.
2.
3.
9-10-15
Electrons are responsible for the atomic _____
(mass or volume)
List the number of protons, electrons and neutrons
for the following elements: B, Ag, & K-40
Which of the following are isotopes?
4
Agenda
Homework
Turn in Penny Lab
Notes Unit 2-4
WS unit 2-4
Online HW
WS unit 2-4
Sept 14 - Quiz unit 2
Sept 18 - Online HW unit 2
Unit 2-4
Electron Properties
Electron Behavior
Electrons exhibit properties of both
particles and waves
 Electrons are located in orbitals, that
correspond to specific energy level
 Electrons can be considered waves
confined to the space around a nucleus

Electromagnetic Spectrum
Light Emission
Electron energy
levels are
determined through
an element’s
emission spectrum
 When electrons
absorb energy, they
change energy
levels within the
atom

Light Emission
However, they are
unstable in this
excited state
 Electrons move back
to a more stable
ground state, by
emitting energy in the
form of light (photon)


http://micro.magnet.fsu.edu/primer/
java/fluorescence/exciteemit/index.
html
Light Emission
The photon (energy packet) that is emitted
will have a different wavelength (color)
depending on the amount of energy that was
released
 Examples light spectrum: Hydrogen and Iron

Light Emission
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Each element has a
different number and
arrangement of
electrons
Therefore, elements
can be identified based
on their emission
spectrum
This is how we know
that the sun is
composed of hydrogen
and helium
Quantum Model

Quantum model - Electrons exist at
particular energy levels in their orbitals
Quantum Model

Electron configurations - indicate the
arrangements of the electrons within the
atom
-These are written using quantum numbers
-Used to pinpoint where an electron is probably
located
Assignments
Check grades
 Notes summary
 Worksheet unit 2-4 (#1-17) need my
initial before class is over
 Online HW unit 2
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