Unit 2 Flashcards
(68 cards)
Planck’s quantum hypothesis
Energy is emitted in small bursts or brackets called a quantum of energy
Photon
A quantum of light energy
The photo electric effect (Maxwell)
Mid 19th C
Light is an electromagnetic wave
The photoelectric effect (Hertz)
1887
The energy of light is dependant on the frequency, not the intensity or brightness of the light
The photoelectric effect (Einstein)
Electrons can absorb foxed amounts of light energy, these energy pockets are called photons
Bohr model
Electrons can be excited to a higher energy level by absorbing a photon and return to a ground state by emitting a photon
“uneven stair case”
The bigger the difference, the more energy the photon has
2n^2
Described the concept of quantized energy levels
Bohr faileurs
His model only worked for the hydrogen atom
Wave or particle
Electrons have properties of both waves AND particles
This idea helped Schrodinger create his wave equation
Orbital
Region around the nucleus where there is high probability of finding an electron. Can only hold 2 electrons with opposite spins
Heisenbergs uncertainty principal
It is impossible to simultaneously know the exact position and speed of an electron within an orbit
Quantum numbers
The energy of each subshell within a shell are not equal
Pauli exclusion principal
No two electrons can have the same 4 quantum values
Aufbau principle
Each electron is added to the lowest energy orbital available
Hund’s rule
One electron occupies each of several orbitals at the same energy level before a second electron can occupy the same orbital
Principle quantum number (n)
Represents the main shell of electrons (1….)
Secondary Quantum number
Divides the shell unto subtle that have slightly different energy levels and tells the shape of the subtle (0- N-1)
Magnetic quantum number (ml)
Describes the orientation of several subshells (-e - e)
Spin quantum number
In each orbital, there is one electron spinning at +1/2 and one spinning at -1/2
Origin of the quantum theory
Energy is not continuous
Stability- Hund’s rule
The lowest energy configuration for an atom is the one with all the orbitals of an energy level filled with one electron before adding the second. Electrons will choose to be by themselves if possible
Diamagnetic
Atoms with no unpaired electrons
Paramagnetism
The spin of the unpaired electrons creates a magnetic dipole moment, they act like tiny magnets
An external magnetic field will cause the spins to align
Isoelectronic ions
Have the same number of electrons
Anomalies in electron configurations
Cr: [Ar] 4s1 3d5
Cu: [Ar] 4s1 3d10
