Chemistry
Chapter 5 – Electrons in Atoms Notes
Name ________________________
Date _________________________
ATOMIC MODEL

See Atomic Model Timeline worksheet for specifics.
ELECTRONS

Quantum Mechanical (QM) Model- This is the currently accepted model of the atom.
o Erwin Schrödinger wrote an equation which describes _______________________________
__________________________________________________________________________.
 These locations are not definite because of the Heisenberg Uncertainty Principle.

Each of the following terms gives a more specific description of where an electron probably is.
In Chemistry…
In CB South, for example…
o Energy level, n
o Sublevel, l
o Orbital, ml
o Spin, s

Energy Levels, no An electron may NOT be found _____
_______________________________.
o Higher n = higher energy (typically)
o n is called the ______________
_____________________________.
o To determine how many electrons fit into a given
energy level, use this formula: _____
o The maximum number of electrons is 32.
o Electrons will occupy
________________________________ first.

Sublevels (subshells), l-
s Sublevel
Shape
Appears
# of Orbitals
Capacity
p Sublevel
d Sublevel
f Sublevel
ELECTRON CONFIGURATIONS


Electron Configurations-

Electron Configuration PRACTICE
o Sulfur (S)
o Chromium (Cr)
o Cobalt (Co)
o Zinc (Zn)
o Strontium (Sr)
o Selenium (Se)
o Molybdenum (Mo)
o Mercury (Hg)
o Antimony (Sb)
o 1s22s22p63s23p4
o Chlorine (Cl)
o 1s22s22p63s23p64s23d10
o Calcium (Ca)
o 1s22s22p63s23p64s23d104p1
Shorthand notation- To write in shorthand electron configuration notation:
o 1st – Find the _________________ that is in the row above the element you want
o 2nd – Write that noble gas's __________ in [brackets]
o 3rd – Then continue with the e– configuration starting with the next element

Ex- Scandium: 1s22s22p63s23p64s23d1 

Ex- Chlorine: 1s22s22p63s23p5 
ELECTRON EXCEPTIONS
 Write the configuration for the following:
o Cr:
o Cu:

What they actually are:
o Cr:
o Cu:

Reason – _________________ sublevels are the most _________________.
____________________ sublevels are not as stable as filled, but more stable than others.
ORBITAL NOTATIONS & THE RULES

Orbital Notations
o Use a ________________ to represent each _____________________.
 s orbitals have _________ line

p orbitals have _________ lines

d orbitals have _________ lines

f orbitals have _________ lines
o Use up/down arrows to represent _________________________.
o Each line can hold a maximum of _____________ electrons.
o Example
Titanium: ___
1s
___
2s
___ ___ ___
2p
___
3s
___ ___ ___
3p
___
4s
FILLING RULES

Aufbau Principle-
o This is the order we get from “reading” the Periodic Table.

Pauli Exclusion Principle-
o This is the electron “spin.” Either +½ or –½

Hund’s Rule –
o They’d rather spread out.
___ ___ ___ ___ ___
3d
ELECTRON IN ATOMS
 Electron Demonstration – try to identify key concepts for electrons moving within an atom…

Flame Tests
o Elements give off characteristic _________________ which can be used to identify them.
o Electrons ____________ energy from the flame (or other heat source).
o When a certain amount of energy is reached, which is called a __________________,
electrons jump to a higher energy level called the _______________________________.
o When the electrons ___________ energy in the form of ______________, this is also
called a photon or unit of light, they fall back to the lowest, most ________________
energy level called the ____________________________.
VISIBLE LIGHT & THE EM SPECTRUM
 Visible light exists as a narrow band of ____________________ that our eyes can detect.
o The colors of the rainbow ________________________.
o Red light has a wavelength of about _____________ nanometers and represents
_________________ frequencies.
o Violet light has a wavelength of about _____________ nanometers and represents
_________________ frequencies.

Wave Statistics
o Amplitude – the __________________ of the wave from zero to crest.
o Wavelength – the distance between ________________________ points in phase.
 Unit:
 Symbol:
o Frequency – the number of cycles (wave peaks)
that occur in a unit of time.
 Unit:
 Symbol:
o Wavelength & frequency are
______________________ related, meaning that
____________ wavelengths go with
____________ frequencies and ____________
wavelengths go with ____________ frequencies.

Wave Equation
o Formula:
o Speed of light is always:
o Example 1 - If the frequency of radiation for yellow light is 5.10 x 1014 Hz, what is the
wavelength?
o Example 2 - What is the frequency of radiation with a wavelength of 5.00 x 10-8 m?

Electromagnetic Spectrum – a grouping of all waves that travel at the speed of light.
ATOMIC EMISSION SPECTRA
 Electrons returning from an _________________ energy level emit ______________ of specific
______________________ (specific bands of color).
 Each element has a ___________________ emission spectra and therefore is a good way to
_______________ an element!
 Additional transitions exist, but we can’t see
them because our eyes only detect visible
light. These series of transitions are called
Lyman, Balmer and Paschen.
 Energy – as an _____________ falls from excited states they release a ________________ of
energy that can be calculated using Plank’s constant and the frequency of the transition.
o Formula:
o Example 1 - The energy given off when an electron transfers from energy level 6 to 5 is
2.66 x 10-20 J.
 What is the frequency?

What is the wavelength?
o Example 2 - If the frequency associated with a transition from energy level 2 to 1 is
2.48 x 1015, how much energy is released?