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Chapters 4 & 5: Learning Targets
Describe characteristics of a wave (wavelength, frequency, energy)
Explain how wave characteristics are related Explain how light and different colors of light are produced Define the electromagnetic spectrum Explain Bohr models including their advantages and disadvantages Determine the electron configuration and/or orbital diagram of any
atom or ion; use these to determine groups, periods and identities of elements along with things such as number of unpaired electrons
Define the periodic trends and be able to compare to elements and explain their difference with regards to these trends
Describe the role of probability in orbital theory Determine if an ion for a given element will be a cation or anion
and explain how each type of ion is formed
Chapters 4 & 5: Key Words
Ground state Excited state Wavelength Frequency Energy Photon Electromagnetic
spectrum Energy level Orbital Valence electron electron configuration
Core electron Alkali metal Alkaline earth metal Halogen Actinide Lanthanide Atomic radius Ionization energy Electronegativity Transition element Main-group element
Section 1: Properties of Light
Pages 91-97 RBQs #1b,1c,6,8 For a chemical reaction to occur, the atoms and/or molecules involved must physically collide with each other
If two atoms react, which part of the atoms will interact with each other first?
The structure and arrangement of _________________________ therefore, is the key to understanding chemical reactivity
Section 1: Properties of Light
Pages 91-97 RBQs #1b,1c,6,8 The arrangement of electrons was determined by studying how atoms absorb and emit electromagnetic radiation, e.g. light
EM radiation is one way that energy travels through space
Section 1: Properties of Light
Pages 91-97 RBQs Page 118 #1b,1c,6,8 EM radiation has 3 characteristics: speed, wavelength, and frequency
The speed of light (c), is a constant for all forms of EM radiation in a vacuum
We will always assume that EM radiation is movingthrough a vacuum
c = 3.0 x 108 m/s
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
The 2nd characteristic of waves is wavelength (λ) Wavelength is the distance between two peaks
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
Frequency (ν) indicates how many peaks pass a given point each second and is the 3rd characteristic
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
Frequency (ν) indicates how many peaks pass a given point each second and is the 3rd characteristic
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
The characteristics are related by the following equation:
Be careful with units! Make sure everybody matches up!
Given that c is a constant, what kind of relationship does this show between wavelength and frequency?
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
The energy of the radiation is also related to the frequency of the radiation
The fun part is that light behave like a wave, but it also shows behaviors characteristic of particles, in this case called photons
The equation below gives the energy of EM radiation, and is equal to the energy of one single photon; QUANTIZED!
Calculate the frequency of light with a wavelength of 6.50 x 102 nm. Also, determine the unit.A. 1.95 x 1011
B. 4.61 x 105
C. 1.95 x 102
D. 4.62 x 1014
What is the increment of energy (the quantum) that is emitted at 4.50 x 102 nm? Determine the unit, also.A. 4.42 x 10-19
B. 4.42 x 10-28
C. 8.95 x 10-32
D. 1.01 x 1048
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
Atoms are normally found in their ground state, which is the lowest energy state of an atom
When an atom absorbsenergy, for example from electricity, the atom entersthe excited state
When the atom is excited, theelectrons move to higher levels
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
Excess energy makes the atom unstable, and the excess energy is released as a photon (light) to return the atom to the ground state
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
White light contains every wavelength of visible light, and products a continuous spectrum
Other times, only certain wavelengths are emitted producing a line spectrum
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
Substances emit different wavelengths because they absorb and emit different amounts of energy due to differing numbers and arrangements of electrons
Each substance has its own unique line spectrum
These can be used to identifyunknown substances
Section 1: Properties of LightPages 91-97 RBQs Page 118 #1b,1c,6,8
Niels Bohr used the idea that electrons can only possess certain amounts of energy to develop the Bohr model; this model showed electrons traveling in fixed, circular orbits
Sadly, Bohr was wrong…atoms with more than one electron blowthis idea to tiny little pieces
But atoms and electrons beingquantized was pretty frickin’ smart of him
Section 2: OrbitalsPage 100
A key development in understanding the structure of the atom was Schrodinger’s wave equation, which lead to quantum mechanics...Heisenberg helped a little, too...
Solving this equation leads to a series of wave functions, which is essentially a set of x, y, and z coordinates
Each point graphed as a result of these coordinates indicates the possible location of an electron
Section 2: OrbitalsPage 100
Graphing a lot of these points gives a map of the probable location of an electron; the exact location of an electron is pretty much impossible to determine
Each point gives a possible electron location; more dotsmeans a higher probability of an electron being there
The area of space in which an electron is most likely to be found is called an orbital
Section 2: OrbitalsPage 100
This is done for every electron they can get their hands on, for example p-orbitals
Notice that there are three ways the p-orbital can be oriented in space…this means there can be three p-orbitals!! Sweet!
Section 2: OrbitalsPage 100
Each orbital (or area of space) can hold a maximum of 2 electrons.
One or more orbitals combine to make sublevels or subshells
The sublevels consist of different shapes of orbitals, and are designated using letters
The four different shapes of orbitals are s, p, d, and f
So an f-sublevel consists of f-orbitals, a d-sublevel consists of d-orbitals and so on…
Section 2: OrbitalsPage 100
Something to help clarify this is to think of an atom as a hotel
If the atom is a hotel, each energy level is a floor of the hotel
The sublevels are different types of rooms on that floor
The orbitals are the individual rooms on each floor
Each room (orbital) has a maximum occupancy of 2 people (electrons)
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36,
37, 40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
Electron configurations and orbital diagrams are used to show the location (probable) of electrons in an atom
Electron configurations use the notation seen below:
Orbital notation looks like this fun stuff down here:
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37, 40, 43,
45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
Electron configurations and orbital notations are determined by applying the relationship between the periodic table and the structure of atoms (which you figured out in your lab)
Let’s find the e- configuration and orbital notation for oxygen...and while we’re at it, say hello to Pauli and Hund!
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
Now how about iron?
And what about bromine?
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
And lets try neodymium (atomic #60) ?
And for fun, lead!
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
What is incorrect about orbital notation below?
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
What is incorrect about orbital notation below?
Which element is represented by the electron configuration
seen below?
A. VanadiumB. ArgonC. IronD. Cobalt
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
Noble gas notation gives a way of shortening the electron configuration and focusing on valence electrons
Element
Electron Configuration Noble Gas Config.
Sodium 1s2s2p63s1 [Ne] 3s1
Argon 1s22s22p63s23p6 [Ne] 3s23p6
Silicon 1s22s22p63s23p2 [Ne]3s23p2
Fluorine 1s22s22p5 [He] 2s22p5
Beryllium
1s22s2 [He] 2s2
Iron 1s22s22p63s23p64s23d6 [Ar] 4s23d6
Lead 1s22s22p63s23p64s23d104p65s24d105p66s25d104f146p2
[Xe] 6s25d104f146p2
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
Based on the noble gas configurations on the previous slide, write steps to use in determining the noble gas configuration of an element.
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
The electron configurations of ions are determined by keeping track of the number of electrons gained/lost and exactly where they are added to or removed from
Metals lose electrons forming positively charged ions called cations
Metals lose electrons from the highest energy level
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
Nonmetals gain electrons forming negatively charged ions called anions
Nonmetals gain electrons in the highest energy SUBlevel
Section 3: Electron ConfigurationsPages 105-107, 110-116, 128-133 RBQs Pages 118-120 #17, 22-30, 36, 37,
40, 43, 45More RBQs Pages 155-158 #6-13a, 14a, 16a, 27-31, 39, 41, 43, 46,49
Write the electron configuration and noble gas configuration for the nitride ion, N3-.
Write the electron configuration and noble gas configuration for the Cadmium ion, Cd+2.
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
The structure of the atom, as reflected in the periodic table, can be used to determine and predict various properties of atoms
Ionization energy: the energy required to remove an electron from a gaseous atom or ion
Atomic Radius: Half the distance between the nuclei of two atoms
Electronegativity: the ability of an atom in a molecule to attract shared electrons
With each property, it is all about how strongly the nucleus of the atom attracts valence electrons; two factors impact this
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Coulomb’s Law illustrates these two factors:
F = electrostatic force q = electric charge r = distance between charge centers k = who cares?
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
So think about this in terms of an atom:
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
The charge factor is about more than just the number of protons in the nucleus
The focus is on the nucleus attracting the valence electrons, so the core/inner shell/shielding electrons must be considered
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
The core electrons cause the shielding effect
Core electron cause a decrease in the amount of attractive pull felt by the valence electron(s)
More core electrons = larger decrease
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
This is summed up by the effective nuclear charge(Zeff)
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Find the Zeff for the following elements; then describe how the Zeff changes moving from top to bottom within a group
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Find the Zeff for the first four elements below; then describe how the Zeff changes moving from left to right within a period
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Distance between the nucleus and the valence electrons is all about the number of energy levels
More energy levels means valence electrons farther from nucleus
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Distance between the nucleus and the valence electrons is all about the number of energy levels
More energy levels means valence electrons farther from nucleus
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
So when comparing two elements in a period, which factor causes them to have different properties? Which is ignored?
And when comparing two elements in the same group, which factor causes them to have different properties? Which is ignored?
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
Ionization energy is the energy needed to remove a valence electron
Does a high ionization energy mean an atom has a strong attraction for its valence electron(s) or a weak attraction?
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
Which has a higher ionization energy: lithium or fluorine? Explain.
Which has higher ionization energy: lithium or potassium? Explain.
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
Electronegativity is the ability of an atom to attract shared electrons when bonded to another atom
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
Electronegativity Values
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
Which has a greater electronegativity: lithium or fluorine? Explain.
Which has a greater electronegativity: lithium or potassium? Explain.
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Atomic radius is defined as half the distance between the nuclei in a molecule consisting of identical atoms
More simply, the atomic radius can be thought of as the size of an atom
Since the boundary of an atom can’t be defined, we can’t just measure from one side of an atom to another
Section 4: Periodic Properties and TrendsPages 140-146, 149-154 RBQs Pgs 156-158 #17-20, 22-26, 32, 33, 35-
38, 45
Which atom is larger: lithium or fluorine? Explain.
Which atom is larger: lithium or potassium? Explain.
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
Changes that occur with ions can be determined similarly; draw a Bohr model for a neutral lithium atom and an lithium ion below. Describe how their radii differ and why this difference exists.
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
Now do the same for a Bohr model for a neutral fluorine atom and a fluoride ion below. Describe how their radii differ and why this difference exists. They are not the same size!!!
Section 4: Periodic Properties and TrendsPages 237-246 RBQs #3, 4, 8, 10, 15-43
And now draw a fluoride ion, and oxide ion, and a sodium ion. Arrange them from smallest to largest, and explain the order selected.
Arrange the following by increasing atomic radius:
Ca, Ni, Br?A. Ni, Br, CaB. Br, Ca, NiC. Ca, Br, NiD. Ca, Ni, BrE. Br, Ni, Ca
Arrange the following in order of increasing ionization energy: F,
Br, IA. I, Br, FB. Br, I, FC. F, Br, ID. I, F, BrE. Br, F, I