University of Toronto
Quantum Mechanics and
Chemical Bonding
Course: CHMA10 Introductory Chemistry I
,Chapter 7 – The Quantum Mechanical Model
h=6.626 x10-34 J∙s c = 3.0 x108 m/s 𝑅= 1.097 x 107
1 1 𝑐
𝐸 = −2.18 × 10−18 ( − )
𝑛 𝜆= 𝑣=
𝑛2𝐹 𝑛2𝑖 𝑚𝑣 𝜆
V is velocity v is frequency
𝑐 𝐸 = 𝑣
𝑣 = = 𝛥𝐸atom = 𝐸photon 𝛥𝑥 ⋅ 𝑚 ⋅ 𝛥𝑣 ≥ = constant
𝜆 𝐸 < 0 absorbed 4𝜋
Heisenberg uncertainty principle
v is frequency 𝐸 > 0 emitted
=𝐸 𝑟𝑎𝑑𝑖𝑎𝑙 𝑝𝑟𝑜𝑏𝑎𝑏𝑖𝑙𝑖𝑡𝑦
𝑝𝑟𝑜𝑏𝑎𝑏𝑖𝑙𝑖𝑡𝑦
𝛿 ℏ2 =
2 = 𝑝𝑟𝑜𝑏𝑎𝑏𝑖𝑙𝑖𝑡𝑦 𝑑𝑒𝑛𝑠𝑖𝑡𝑦
𝑖ℏ (𝑟𝑡) = − 𝛻2 (𝑟, 𝑡) + 𝑉(𝑟, 𝑡) (𝑟, 𝑡)
𝛿𝑡 2𝑛 𝑢𝑛𝑖𝑡 𝑣𝑜𝑙𝑢𝑚𝑒 ⋅ 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑠𝑒𝑙𝑙
Quantum number bank
Name Symbol Value Property
Principle n Positive integers Energy level
Angular momentum 𝑙 0 to (n-1) Shape
Magnetic 𝑚𝑙 Integers -𝑙 to +𝑙 Orientation
Spin 𝑚𝑠 + 1⁄2 to − 1⁄2 Spin
Electromagnetic Radiation Spectrum
, Absorption spectrum is formed by shining a beam of white light through a glass prism which indicates
the wavelengths of light that have been absorbed.
Alpha Particles have 2 p+ and 2 n0
Anion forms by adding electrons.
Atomic Emission Spectra, every element has its own unique bright light spectrum which can be used to
identify elements.
Aufbau Principle tells us the order we need to fill electrons in. Electrons occupy lowest energy orbitals
first.
Blackbody Radiation is a theoretical object that absorbs all radiation that falls on it and re-emits it with
a broad range of frequencies mostly in the visible light spectrum, but they do not emit UV light. Intensity
of the radiation varies with frequency, when frequency is higher, temperature increases.
Bohr applied quantization to atomic spectra and developed a mathematical model of the atom with
discrete energy levels. Electrons orbit the nucleus, as orbital radius increases, energy increases.
Monochromatic radiation is emitted or absorbed when an electron moves energy levels.
Born realized squaring the wave function gave a probability density known as an orbital
Broglie predicted that electrons have wave particle duality. Electrons have the double slit diffraction
pattern. Using a double slit experiment with a laser between the slits and the screen to see which slit
the electrons go through creates a particle pattern since the laser changes the nature of the electron.
Cation forms by removing electrons.
Chromium has an electron configuration of [Ar] 3d5 4s1 which provides added stability since avoiding
paring electrons adds stability.
Constructive Interference is when two waves are in phase, one wavelength apart, and the amplitude
doubles.
Copper has an electron configuration of [Ar] 3d10 4s1 because having all 3d orbitals filled is more stable
than having a full 4s orbital and 4 and a half filled 3d orbitals.
Dalton hypothesized the law of conservation of mass, the law of definite proportions, and that atoms
are indivisible.
Degenerate when orbitals have equal energy.
Destructive Interference is when two waves are out of phase, half a wavelength and the amplitude is
zero.
Diamagnetic, when there are no unpaired electrons, so the magnetic field cancels out and the species is
slightly repelled by an external magnetic field.
Diffraction is the bending of waves around obstacles and opening