Quantum Theory
electromagnetic spectrum
All of the frequencies or wavelengths of electromagnetic radiation
The Secondary/Azimuthal/Angular Momentum Quantum Number
Began with Arnold Sommerfeld, who after discovering that each line in the emission spectrum was actually a series of numbers, theorized that each energy level or shell was made up of one or more subshells. The second quantum number, l, describes the *shape* of an orbital(subshells). The value of l ranges from *0 to n-1*. Value of l- Letter designation: 0-s(sharp), 1-p(principle), d(diffuse), f(fundamental) *Shapes* s-orbital=sphere, p-orbital = dumbbell. Possible orientations: s=1, p=3, d=5, f=7
photoelectric effect
The emission of electrons from a material when light of certain frequencies shines on the surface of the material. Showed that the *frequency* of light determines the energy of the e- released. Led to the rise of *quantum theory*
wave-particle duality
electrons and light can behave as both a wave and a particle
matter wave theory
electrons have both wave and particle properties
Energy and wavelength
inversely proportional, the lower the wavelength, higher the energy.
Louis de Broglie's research suggested that
light is made of photons that behave like EM waves, therefore having properties of waves
Heisenberg uncertainty principle
states that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle. The act of measure one value changes the other. Therefore the location of e- is expressed as a probability.
Principle quantum number
symbolized by n, describes the *size and energy* of an orbital(the main shell of an e-). The larger the value of n, the further an e- is from the nucleus, and the greater the energy of the e-. *The value of n for an atom is equal to its period number
Max Planck
theorized that light is made up of small, high speed bursts of energy of a specific size, known as quanta(plural) or quantum(singular), which could be measured.
de Broglie equation
λ = h/mf; λ - wavelength(m), h - Planck's constant: 6.262*10^-34 J/Hz, m - mass of object(kg), v - speed of object(m/s)
4 quantum numbers
1. Principal Quantum Number - n 2. Secondary quantum number(Azimuthal or Angular Momentum quantum number) - l 3. Magnetic quantum number - m sub l 4. spin(magnetic) quantum number - m sub s
Planck equation
E=hf (E=energy per photon, f=frequency, h=Planck's Constant=6.262*10^-34 J/Hz)
Who coined the term photon
Einstein used Planck's equation to explain photoelectric effect, referred to individual particle of light as a photon Therefore, higher energy light(UV) has a larger quanta than lower energy light(IR)
The magnetic quantum number
Sommerfeld explained that the different shaped subshells can exist at different positions or angles. The magnetic quantum number, *m sub l*, describes where one e- is located, relative to another. Value range from *-l to +l*. - each subshell can hold 2 e- max - the total number of suborbital in a shell is equal to n^2
The spin (magnetic) quantum number
Wolfgang Pauli discovered that e- in e- pairs are constantly rotating with equal magnitude in opposite directions. The spins create electrical charges. therefore opposite spin creates opposite charges. The attraction between e- pairs created by opposite electrical charges is *greater than* the repulsion caused by the e-'s like charges. The spin quantum number, *m sub l* describes the spin of an e- on its own axis. Values can be: *-1/2 or +1/2*. Unpaired spinning e- results in an additive electrical force that creates a weak force of magnetism known as *paramagnetism*. (ferromagnetism is associated w/ metals). If there is no overall magnetic force, the atom is *diamagnetic*.