Atomic Structure
Wavelength(λ) measured in m or nm
How many nm is 3.45x10-7m?
Frequency(ν) measured in Hz or s-1
Speed of light c=3.00 x108m/s
Planck’s constant h=6.63 x10-34 J·s
c= λ ν
ν=c/ λ
λ=c/ ν
Green light has a wavelength of 520nm.
What is frequency?
Energy absorbed when electron jumps to higher
energy level.
Energy released (emitted) when electron falls back
down to lower energy level.
Which energy level jump/fall releases/absorbs the
most energy?
E=h ν
Calculate the energy in joules of a photon with a
wavelength of 6.0 x104nm.
The wavelength of light with enough energy to
mutate a strand of DNA is 25.0nm. Calculate the
minimum energy to do this in kJ/mol.
What is the wavelength of a photon emitted when
an electron travels from n=5 to n=3 in a hydrogen
atom?
ΔE= -2.178x10-18J (1/nf2-1/ni2)
Quantum Mechanical model
Orbital-regions of space where there is
approximately 90% probability of locating an
electron.
Quantum numbers
n
-energy level
l
-shape of the orbital
s=0, p=1, d=2, f=3
ml
-orientation of orbital
If l=0, ml=0
If l=1, ml=-1,0,1
If l=2, ml=-2,-1,0,1,2
ms
-spin
+1/2 or -1/2
Which element has an outermost electron
described as (3,1,-1,+1/2)
(4,0,0,+1/2)
Which set of quantum numbers is not possible?
a. 1,0,0,1/2
b. 1,1,0,1/2
c. 1,0,0,-1/2
d. 2,1,-1,1/2
e. 3,2,1,1/2
Diamagnetic vs. paramagnetic
Diamagnetic-all electrons are paired-repelled by
magnets
Paramagnetic-one or more unpaired electronsattracted to magnets
Electron configuration
Aufbau-electrons fill orbitals of lowest energy first
Pauli exclusion-2 electrons per orbital
Hunt’s Rule-fill equal energy orbitals 1 electron
per orbital before doubling up
Heisenberg Uncertainty Principle- you can never
simultaneously know the exact position and the
exact speed of an object.
Dual-slit experiment-light has both particle and
wave characteristics.
Write the electron configuration for Ba.
Write the electron configuration for Mn2+.
Periodic Trends-2 factors that affect
1. Effective nuclear charge-more p+ and e-, more
nuclear charge. Increases left to right.
2. Nuclear shielding- e- in lower energy levels
“shield” the electrons in higher energy levels.
Attractive force is less for those valence
electrons. Increases top to bottom.
Atomic radius
Decreases across, increases top to bottom
S, O, P??
Si, Na, Mg??
Ionization Energy-amount of energy needed to
remove an eLi(g)
Li+(g) + e-
Increases left to right, decrease top to bottom
Explain exceptions:
Why is Be higher than B?
Why is N higher than O?
Predict the group in the periodic table in which an
element with the following ionization energies would
most likely be found.
1st IE = 786 kJ/mol
2nd IE = 1577 kJ/mol
3rd IE = 3232 kJ/mol
4th IE = 4355 kJ/mol
5th IE = 16,091 kJ/mol
6th IE = 19,784 kJ/mol
Ionic radius-compare p+ pulling on eN3-, Be2+, O2Mg2+, Ca2+, Al3+
Electron Affinity-energy change that occurs when
an electron is added to a gaseous atom.
F(g) + e-
F-(g)
Electronegativity-attraction of electrons to an atom
F is largest-highest nuclear charge, least shielding
Fr is smallest, lowest nuclear charge, most
shielding
Increases left to right, decrease down
N, P, O??
F, O, Li, Na, K, Be
Which element is least electronegative?
Which element has the lowest ionization
energy?
Which element has the smallest naturally
occurring ion?
Which element has the smallest atomic radius?