Week Three Flashcards
White Light
passed through a prim, separates into a continuous spectrum of colours
Light Spectrum
consists of mainly black background, and a series of line at different wavelengths
- each element produces its own unique line specturm
Maxwell’s Theory
light consists of electro-magnetic waves. that travel in at 3.0 x 10^8ms^-1
Speed of light symbol
c
h
wavelength
v
frequency
frequency formula
frequency = speed/wavelength
Planck Theory
elements emit or absorb light energy in discrete amounts.
- the energy of a quantum (E) is the amount that can be emitted (or absorbed) in the form of radiation
Quantum Energy Formula
E= Hv where H is planck’s constant
Planck’s Constant
6.63 x 10^-34Js
Bohr’s Theory
- electron occupy discrete orbitals
- Energy is not radiated continually
- absorption of fixed quantities of energy occurs
- emission of fixed quantity of energy occurs
- electrons have spin
Addition of heat to electrons
atoms absorb the energy and electrons jump to higher energy levels
- after a while, electrons return to a lower level and energy is released as light
how energy difference between shells is measured
by measuring the wavelength or frequency of light emitted
Energy difference formula
DE= hV where v is frequency
Electron wavelength behaviour
behave like standing waves
- occupy discrete electronic energies
Quantum Numbers
4 numbers
- principal quantum number (n)
- angular momentum number (L)
- magnetic quantum number(ml)
- spin quantum (ms)
Principal quantum number (n)
shells of electrons are number by their principal quantum number
n=1 shell has up to 2 electrons
n= 2shell has up to 8 electrons
Shell structure
the potential energy increases as the distance of the shell from the nucleus increases
- gaps between the amount of energy needed decrease as you move up the shells as you need less energy to move between shells
increasing the number of protons
decreases the energy of all shells and moves them closer to nucleus
Angular Momentum Quantum Number
each shell consists of sub shells
- l has possible values ranging from 0 to n-1
Angular Momentum Quantum Number - first shell
s orbital
Angular Momentum Quantum Number - second shell
s and p orbital
Angular Momentum Quantum Number- third shell
s, p and d orbital
Angular Momentum Quantum Number - fourth shell
s,p,d and f orbitals
orbital energy increase
increases as the shells go across the periodic table
Magnetic Quantum Number (Ml)
orientation and orbital direction
- tells how many orbitals there are for the l value
l = 0
s orbital - one
l = 1
p orbital
- ml = +1,0,-1
3 p orbitals
l = 2
d orbitals
- ml = +2,+1,0,-1,-2
l= 3
f orbital
- ml= +3,+2,+1,0,-1,-2,-3
Electromagnetic radiation
Used to study structures of atoms
What has Wavelength properties
Light
Frequency
Variation of wavelength
- number of wave crests passing a point in space in one second
Wavelength
Variation in space, distance between wave crests
Amplitude
Max displacement of a wave from midline
Increasing amplitude
Increases light
Speed of light
2.998 x 10^8ms-1
Speed of light formula
Frequency/ wavelength
Photoelectric effect
Energy (light) absorbed by an organism and passes onto organism
Photons
Packets/ bundles of light
How atoms can form higher energy state
Absorb photon of particular energy
Absorption spectrum
Dark lines on visible
Emission spectrum
Coloured lines on dark background
Wavelength of electron
Wavelength = h/mu
Atom bound electron - energy
Quantised energy
Free electrons - energy
Any
Nodes
Area zero electrons density in orbital
Increases as n increases
S orbital electron distribution
Spherical
P orbital - electron distribution
Dumbbell
- 2 ends of dumbell different phases
D orbital - electron distribution
Clover shaped - 4/5
Dz2 - dumbbell with doughnut around
Phase
Starting point ofwave with respect
Orbital energy
Determined by atomic number z and principal quantum number n
Ionisation energy
Energy of orbital
Energy required to remove electron completely from orbital
Aufbau principle
Orbitals are filled in order of increasing energy
Pauli exclusion principle
No two electrons in same atom can have the same quantum numbers
Hunds rule
Electrons occupy sets of degenerate orbitals so to give max number of unpaired spins
Paramagnetic
Will attract magnetic field
Atoms with unpaired electrons
Diagmagnetic
Not attracted to magnetic field
De broglie equation
Links wavelength of particles with speed and mass
P = h/ wavelength
Squaring wavelength
Gives electron density
S electrons
Higher attraction to nucleus
Potential energy is lower than other orbitals
ISOelectric
Same number of electrons, same ground state electron configuration
Core electrons
Increases as atomic number z increases
Force of attraction between nucleus and electron in inner shell is stronger
Valence electrons
Occupy orbitals in outer shells
Are used in bonding
Greater positive charge
Closer the electrons are to the nucleus
Smaller the atom
Shielding
Electrons closer to the nucleus shield the positive pull from outer electrons
Can be shielded by closer shell or same shell
Effective nuclear charge - Zeff
Every electron is attracted to nucleus and repelled by other electrons
Charge felt by electron
Zeff formula
Zeff = Z - 6
Where z is actual nuclear charge and 6 is shield constant more than 0 but less than atomic number
Across period - charge
Charge increases, size decreases
Down group - charge
Charge increases
Metallic radii
Half distance between metallic nuclei
Covalent radii
Chemically bonded to non metallic nuclei
Atomic radii
Increases down group
Decreases along rows
Ionic radii
Radius of charged ion
Radius decreases when atom forms cation
Radius increases when anion is formed
