atomic orbitals (pike) Flashcards
what are the charges of protons electrons and neutrons
proton = 1.6910^-19 faradays constant
electron =-1.6910^-19
neutron = 0
what are the relative charges of protons electrons and neutrons
proton = +1
electron = -1
neutrons = 0
what are the relative masses of protons electrons and neutrons
protons = 1837
electrons = 1
neutrons = 1837
what 2 numbers are atoms characterized by and what do they mean
atomic number Z - number of protons
mass number N - number of neutrons and protons
define isotopes, atomic mass and allotropes
Isotopes - atoms of the same element with a different number of neutrons
Atomic mass (A) - weighted average mass number of all isotopes present
Allotropes - different structural forms of a bulk element due to different spatial arrangement
outline the timeline and development of the atom
1808 - Dalton atom are indivisible
1904 - Thomson electrons surrounded by a soup of positive charge ( plum pudding model)
1911 - Rutherford atoms consisting of electrons moving around a nucleus
1913 - Bohr electrons around the nucleus but only certain energies allowed
post 1930 - Heisenberg orbitals
how do we prove the structure on atoms
One of the best ways of proving the structure of proving the structure of atom is through the interactions with electromagnetic radiation and it is described by its wavelength and frequency
what did louis de Broglie propose
Louis de Broglie proposed that if electromagnetic radiation could exhibit the properties of waves and particles, so could electrons (and every moving particle) also known as wave-particle duality
what is the Heisenberg uncertainty principle
it is not possible to determine the position and momentum of an electron at any particular instant in time
since we cannot determine the exact position and velocity of electrons what do we do instead
calculate the probability of finding an electron in a particular place
what is a node
points where displacement from center is zero
what is a boundary condition
requirement of a wavefunction to have a certain value at a certain point.
quantisation is due to the ends of the strings being fixed
what is the equation for the speed of light
speed of light = wavelength * frequency
speed of light 3*10^8 m/s
define wavelength
the distance between two peaks or two troughs of a wave
describe what happens when behaviors of electromagnetic radiation has properties of a wave
it will have a wavelength and a frequency, and when it goes through a small gap you will get diffraction patterns when you get constructive and destructive interference when two waves get wide
describe what happens when behaviors of electromagnetic radiation has properties of a particle
it has to have a certain mass and it has to have a certain energy and has to have discrete amount of it called quanta (quantisation). particle is a specific amount of energy of one kind of electron
what is the equation for energy of a particle
energy = planks constantfrequency planks constant = 6.2610^-34
describe Bohrs model of the atoms
Bohr introduced the idea of quantisation , and said that the electrons move around the nucleus in orbitals at a fixed distance. each orbit has a fixed radius, is given a quantum number and has a certain energy. the energy of an electro is based upon its quantum number
what happens when an electron moves down to a lower energy level
the excess of energy is emitted as a quantum of light, the change in energy is the change of the quantum of light
why does Bohrs model of quantisation only work for hydrogen
hydrogen only has one electron, when you have more than one electron, with other elements the electrons are going to repel so they are interacting with each other and not just the nucleus
what is the equation for momentum
p=mv
momentum = mass*velocity
how do you measure the position of an electron
needs to interact with a photon, due to the small size of electrons, suitable electromagnetic radiation will be very energetic. photons also have particle - like properties and will change the momentum of electrons
what is an orbital
- Orbitals describe the electron density (probability for finding an electron) in space
cloud of probabilities
what is a wave function
The mathematical function used to calculate the shape of atomic orbitals is called a wavefunction. wavefunctions are a mathematical functions of a position in space and has a single value at each position