Electron Configurations
Practice Problems:
Write the electron configuration notation for each of the following
atoms:
• Hydrogen
• Carbon
• Iron
• Bromine
↑
1s
↑↓ ↑↓
↑
↑
1s 2s
2p
↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓
1s
2s
2p
3s
↑↓ ↑↓ ↑↓ ↑↓↑↓ ↑↓
1s 2s
2p
3s
↑↓ ↑↓↑↓
↑↓
3p
4s
↑↓ ↑↓↑↓
3p
↑↓ ↑
↑ ↑ ↑
3d
↑↓ ↑↓ ↑↓↑↓↑↓↑↓ ↑↓↑↓ ↑
4s
3d
4p
Shorthand Method: Assumes we already know about the # of
•H
•C
• Fe
• Br
1s1
1s2 2s2 2p2
1s2 2s2 2p6 3s2 3p6 4s2 3d6
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5
□.
How Electron Configurations Relate to the
Organization of the Periodic Table
s
p
d
f
Orbitals being filled for elements in various parts of the periodic table:
•
•
•
Electron Configurations & Properties
How do electron configurations relate to the chemical and physical
properties of an element?
All elements with the _________
same outer shell e- configurations have
the ________
similar properties.
This means that elements in the same ____________
vertical
group have
similar properties.
Examples: (1) Li, Na, K, Rb, and Cs all have __
1 lone “__”
s e- for their last
orbital... (_____,
2s1 _____,
3s1 _____,
4s1 etc.) This makes all of them ___________
very
reactive. They all react with __________
to produce hydrogen gas.
water
(2) Ne, Ar, Kr, Xe, and Rn all have the outer energy level completely
filled with electrons...(________,
3s2 3p6 ________,
__________
2s2 2p6 ________,
4s2 4p6 etc.) This makes all
inert
of them ______________.
They do not produce ________________
.
compounds
(3) Since SiO2 can be a ceramic, SnO2 may be as well.
More Practice Problems
(1) Which element has its last electron as a 4p5? ___________
Bromine
F, Cl, I, At
(2) Which elements are similar in properties as Bromine? __________
(3) What would the last outer shell electron configuration look like for
the element underneath Radon, (Rn)?
…7p6
3d1
(4) Which electron is added after 4s2? ________
sphere
(5) What is the shape of the last orbital filled in Calcium, (Ca)? _____
4
(6) How many electrons are in the last “p-orbital” of Sulfur, (S)? ____
(7) Would you expect the element underneath Francium to react
violently with water? Yes…the
_____ other Group 1 metals do too.
Electron Dot Notation
• When atoms form bonds, only the outermost electrons are involved. These are called
the “valence” electrons.
• The inner electrons are called “core” electrons.
• The electron dot notation (sometimes called the Lewis Structure) is a way to represent
the valence electrons.
• The “Group A” number on the periodic table equals the # of valence electrons and
therefore the # of dots.
How Light is Produced
•
•
When atoms get hit with energy
(by _____________
zapping
them with
heating
electricity or by ____________
them up), the valence e− absorb
jump
this energy and __________
to
a higher energy level called an
“excited state”. Figure (a)
As they immediately fall back
ground
down to the “____________
state”, they give off this energy
in the form of a particle of
light
___________
(or other types of
electromagnetic radiation)
called a _________.
photon Figure (b)
How Light is Produced
•
•
Each photon emitted has a
color
specific ___________
(or
frequency).
The color of the light that is
given off depends on how
far the electron _______
fell
_____
(which depends on how big
of a jump it originally made.)
The farther the fall, the
greater
___________
energy the
photon has.
Photons of red and blue light.
How Light is Produced
•
•
Since electrons are located only in certain __________
energy levels (or
orbitals) around the nucleus, only certain specific _________
color of light
are emitted.
spectroscope
Scientists use a _________________
to separate these colors into
bar code of color
bands of light. These bands of color look like a ______
which is characteristic of that element. No two elements produce the
spectrum
same ______________
of colors. This can be used to distinguish one
element from another contained in a sample.
Emission Spectrum
Hydrogen
Spectrum
Neon
Spectrum
Measuring the Energy of Photons
• The photons of light given off or absorbed by atoms have specific
energies that can be calculated according to the following formula:
E=hν
(E = h f…some textbooks write it this way.)
E = energy (in joules)
h = Planck’s constant = 6.63×10−34 J·s
ν (nu) = frequency of the light in units of Hertz (waves per second)…s-1
• The frequency of light can be determined if given the wavelength
(in meters) according to the following formula:
c=λν
(c = f λ…some textbooks write it this way.)
c = the speed of light = 3.0 x 108 m/s
λ (lambda) = wavelength (in meters)
Both of these equations are given to you on the AP Equation Sheet.
The Energy of
Hydrogen’s
Four Visible
Photons
All the Photons Produced by Hydrogen
Counting p+, no and e− in an Atom
• Protons = Atomic Number
• Electrons = protons (in a neutral atom)
• Neutrons = Mass # − protons
• Mass Number = protons + neutrons
Ions
Gaining electrons gives an atom a (−) charge.
Losing electrons gives an atom a (+) charge.
Isotopes
• An isotope refers to atoms that have the same # of ___________,
protons
neutrons
but they have a different # of ___________.
mass #’s (or simply,
• Because of this, they have different _________
masses
different ___________.)
• Isotopes are the same element, but the atoms weigh a different
neutrons
amount because of the # of ______________.
Examples---> (1) Carbon-12 & Carbon-13
(2) Chlorine-35 & Chlorine-37
(The # shown after the name is the mass #.)
• For each example, the elements have identical ___________
#’s,
atomic
(# of p+) but different _________
mass #’s, (# of n0).
• Another way to write the isotopes in shorthand is as follows:
12
6
C
35
17
Cl
mass #, and the bottom # is the __________
atomic
The top number is the ________
subtracting
number. Calculating the # n0 can be found by _____________
the #’s!
Isotoprah
One of two or more Oprahs having
the same social security number
but different mass numbers
Two Isotopes of Sodium
Mass Spectroscopy
• The discovery of concept of isotopes altered Dalton’s
Atomic Theory…atoms of the same element can have differences!
• A mass spectrometer can separate atoms by mass, and it
can determine the % abundance of each isotope.
Mass Spectroscopy
• Mass spectroscopy explainedhttps://www.youtube.com/watch?v=tOGM2gOHKPc
• Mass spectroscopy data used in calculating the average atomic
masshttps://www.youtube.com/watch?v=KF9_f7uRMoY
Sections of the Periodic Table
More Sections of the Periodic Table