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active recall for AH chemistry-first two topics - Coggle Diagram
active recall for AH chemistry-first two topics
The different types of radiation arranged in order of wavelength is known as the electromagnetic spectrum
Red light has a shorter wavelength, and blue light has a longer wavelength
red light has a bigger frequency, and blue light has a smaller frequency????
When an atom emits a photon, this creates a spectrum made up of a series of lines at discrete (quantised) energy levels
Electromagnetic radiation can be described in terms of waves and characterised in terms of wavelength and frequency
frequency is the number of waves passing a particular point in one second
f=c/lambda
wavenumber= 1/lambda
velocity c= f times lambda
wavelength is the distance between two identical points on a wave
electromagnetic radiation can be described as a wave (as it has wavelength and frequency) and as a particle, and so it is said to have dual nature
in atomic spectroscopy, the concentration of an element is related to the intensity of light emitted or absorbed
to make an emission spectrum for a compound, you measure the intensity of light emitted at different wavelengths
in emission spectroscopy, high temperatures are used to excite electrons within the atom. As electrons drop back down to lower energy levels, photons are released
to make an absorption spectrum for a compound, you measure how the intensity of absorbed light varies with wavelength
in absorption spectroscopy, electromagnetic radiation is directed at an atomised sample. Radiation is absorbed as electrons are promoted to higher energy levels.
electromagnetic waves travel at the same speed(3.00 times 10^8 m/s) and are usually measured in nanometers (nm)
avagadro's constant=6.02 times 10^23 mol -1
planck's constant= 6.63 times 10^-34 J s
when light is emitted or absorbed by matter, it behaves like a stream of particles. These particles are known as photons
when an atom absorbs light, an electron is promoted to the excited state. This excited state is unstable, and so the electron soon falls back down. When this happens, a packet of energy (quantum) or a photon is released for each electron transition
electron configuration
1s 2s 2p 3s 3p 4s 3d
what are the four quantum numbers?- principal quantum number, angular momentum quantum number, magnetic quantum number, spin magnetic quantum number
principal quantum number n
angular momentum quantum number l
magnetic quantum number ml
spin magnetic quantum number ms
describe the different quantum numbers
angular momentum quantum number determines the shape of the sub shell and can have values between -l and +l
magnetic quantum number determines the orientation of the orbital and can have values between zero and n-1
principal quantum number indicates the main energy level for an electron and is related to the size of the orbital
spin magnetic quantum number determines the direction of spin and can have values of -1/2 or +1/2
orbital box notations
It is possible to describe an electron in any atom using the four quantum numbers
Electrons have a fixed amount of energy called quanta
photons have quantised energy that is is proportional to the frequency of radiation
different rules
hunds rule states that when degenerate (equal energy) orbitals are available, electrons fill these orbitals up singly before pairing up with opposite spins
the Aufbau principle states that electrons fill up orbitals in order of increasing energy ie lowest energy orbital first
pauli exclusion principle states that no two electrons in the same atom can have the same four quantum numbers