Eric Zhu, Aditya Apte, & Josh Gallic
Electrons Review Sheet
Key Terms and Equations
Electrons (e-): subatomic particles with a negative elementary charge
Wavelength (λ): distance between identical points on successive waves
Amplitude: vertical distance from the midline of a wave to the trough or peak, responsible for
brightness and intensity.
Frequency(𝝂): Number of Waves that pass through a particular point in one second.
Speed of a wave= λ*𝝂=c c=speed of light in a vacuum=3.00 x 108
Energy of a wave= E=h*𝝂
Planck’s constant=h (6.63 x 10^-34J x s)
Wavelength of a large object: h/mu h=Planck’s constant, m=mass in kg, u=speed in m/s
Electromagnetic Radiation: The emission and transmission of energy in the form of
electromagnetic waves.
Planck discovered that light is emitted or absorbed in distinct packets, called quanta
Photoelectric Effect: The emission of electrons when light shines on a the metal
Photon: A “particle” of light
Ground State of electrons: all electrons at lowest energy potential
Excited State of electrons: electrons gain energy and are boosted to a higher energy level.
Emission: An electron falls to a lower energy level, and a photon is emitted.
Absorption: Energy must be added to an atom in order to move an electron from a lower
energy level to a higher energy level.
Bohr’s Model of the Atom:
En=-RH(1/n2) Ephoton = DE = Ef - Ei
DE=RH(1/ni^2-1/nf^2)
n=energy level, RH= Rydberg constant=2.18 x 10-18J
- e- can only have specific (quantized) energy values.
- light is emitted as one electron moves from a higher energy level to a lower one
Dual Nature of Light and Matter: De Broglie reasoned that an e- is both a particle and a wave.
Heisenberg Uncertainty Principle: We cannot know an electrons exact position or speed at the
same time. we can only know one or the other.
Line Spectrum: a way to identify elements due to the different number of electrons and thus
different energy level changes and different light emissions.
Electrons can only move with a quantum of energy, no way to jump in the middle of energy
levels.
Schrodinger Wave Equation: An equation that describes both the particle and wave nature of
the electron.
Electron Configuration: How Electrons are distributed throughout the various orbitals of an
atom.
Aufbau Principle: electrons are placed into energy orbitals one at a time starting at the lowest
possible energy orbitals.
Pauli Exclusion Principle: an orbital holds a maximum two electron with opposite spins
Hund’s Rule: electrons are placed into energy levels equally so that the most unpaired electrons
possible results
Quantum Numbers(n,l,ml,ms)
n: energy level, 1,2,3,4...etc
l: orbital, 0=s orbital, 1=p orbital, 2=d orbital, 3=f orbital
ml: orientation of orbital, p orbital=-1,0,1; d orbital=-2,-1,0,1,2; f orbital=-3,-2,-1,0,1,2,3
ms: spin of electrons, +½, -½
Electromagnetic Spectrum:-
Electron Orbitals of An Atom:
Electron Questions
1.
Calculate the speed of a wave whose wavelength and frequency are 18.9 cm and 93.7
Hz respectively.
2.
Calculate the energy in Joules of a wave with a wavelength of 7.96*10^3 nm.
3.
Calculate the wavelength of “the particle” in this case: the fastest free kick in soccer was
clocked at 131 mph, or 59 m/s. What is the wavelength associated with a 1 kg ball moving at
this speed in nm?
4.
What is the Ground State Electron Configuration of At, using the noble gas method?
5.
Write the four quantum numbers for the valence electron of K.
6.
Calculate the total number of electrons that can be present in the principal level for
which n = 4.
7.
What principle states that it is impossible to both the exact location and momentum of
an electron at one time?
8.
What two numerical values can s have?
9.
How many minutes would it take for a gamma ray to travel from the sun to Earth?
(Average distance from the Sun to the Earth = 93 million miles)(Round to the nearest minute)
10.
What is the wavelength of a photon emitted during a transition from the n i=4 state to
the nf=1 state in the hydrogen atom, in nm?
11.
Write the ground state electron configuration for Mt
12.
Write the electron configuration for U (noble gas method).
13.
Write the ground-state electron configuration for Ta.
14.
Write the electron configuration for Cn.
15.
Write the electron configuration for Au.
Answer Sheet
1. 17.7m/s
2. 2.50*10^-20J
3. 3.91*10 nm
-23
4. [Xe]6s , 4f , 5d , 6p
2
14
10
5
5. 4,0,0,+½
6. 32
7. Heisenberg Uncertainty Principle
8. +½, -½
9. 8min
10. 97.3nm
11. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d10, 6p6, 7s2, 5f14, 6d7
12. [Rn] 5f3 6d1 7s2
13. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d3
14. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d10, 6p6, 7s2, 5f14, 6d10
15. 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d9