Chapter 5: Electrons in Atoms Flashcards
Equation Relating Speed Of Light To Wavelength And Frequency
c = (gamma)v
c = speed of light - 3.0 x 10^8 m/s
gamma = wavelength (m)
v = frequency (Hz or s^-1)
Equation Relating Energy To Planck’s Constant And Frequency
E = hv
E = Energy (J)
h = Planck’s Constant - 6.63 x 10^-34 (J)(s)
v = Frequency (Hz or s^-1)
Light’s Dual Nature
Waves of electromagnetic radiation or bundles of energy (quanta or photons)
Frequency
Number of waves passing a given point per unit of time
Wavelength
Distance from trough to trough or peak to peak
Amplitude
Vertical distance from peak to trough
Relation Between Frequency And Wavelength
Inverse relation
Order Of Electromagnetic Spectrum (Largest–>Smallest)
Radio, Microwave, Infrared, Visible (Red, Orange, Yellow, Green, Blue, Indigo, Violet), Ultraviolet, X-Ray, Gamma Ray
Heisenberg Uncertainty Principle
It is impossible to know simultaneously the velocity and location of a moving object
Electrons In Atoms
- Electrons are in the electron cloud
- Electron cloud has energy levels - layers in electron cloud that differ by energy of electrons & distance from nucleus
- Sublevels - areas in an energy level in which all electrons have the same energy
- Orbitals - regions in a sublevel that can hold up to 2 electrons
Sublevels (Types And Nature)
Differ in energy & number of electrons
s: 2 electrons (1 Orbital)
p: 6 electrons (3 Orbitals)
d: 10 electrons (5 Orbitals)
f: 14 electrons (7 Orbitals)
Energy level number = Number of sublevels (5 or more theoretical)
s Orbitals
Spherical shape; radius increases with energy level number; more dense in center
p Orbitals
Two lobes with a node between them
d Orbitals
Four of the five d orbitals have 4 lobes; the other resembles a p orbital with a doughnut around the center
Atomic Models
- Rutherford - Positively charged nucleus surrounded by electron cloud; ground state + energy = excited state
- Bohr - Energy levels
- Quantum-Mechanical (de Broglie’s Wave-Particle Duality) - All objects have a wave-like character, but that character is inversely proportional to the mass of the object
Ground State
All electrons in lowest energy position
Excited State
Some electrons further from nucleus than normal
Ways To Describe Electron Location
- Orbital Diagrams
- Electron Configuration
- Shorthand Configuration
- Dot Diagrams
Electron Configuration
- Aufbau Rule
- Hund’s Rule
- Pauli Exclusion Principle
Aufbau Rule
Atoms fill in the orbitals of lowest energy first
Hund’s Rule
If several orbitals of equal energy exist, one electron goes in each orbital before any one orbital is filled
Pauli Exclusion Principle
Electrons in same orbitals have opposite sides
Relative Energy Of Orbitals
ns < np < nd < nf
Order Of Energy Of Orbitals (Lowest –> Highest)
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p
Orbital Diagram
- Each box represents one orbital
- Half arrows represent electrons
- Direction of arrow depends on relative spin of the electron
Shorthand Configuration
Electron configuration using noble gas as baseline
Ex: Mn - [Ar]4s^23d^5 instead of 1s^22s^22p^63s^23p^64s^23d^5
Kernel
Nucles & inner layers of electrons (unchanged in chemical reactions)
Valence Shell
Outer layer of electrons (changes in chemical reactions)
Dot Diagrams (Lewis Structures)
Element symbol with valence electrons around
