Unit 1 Topic 1 ✓ Flashcards
Inorganic Chemistry: Electromagnetic radiation and Atomic Spectra
What is Radiation?
Radiation is the emission of energy as either electromagnetic waves or as moving subatomic particles called photons
NOTE: These particles are high-energy and cause ionisation
What is the Electromagnetic spectrum?
The EM spectrum is the different types of radiation arranged in order of wavelength
NOTE: All EM waves travel at the speed of light
What is Wavelength? (ƛ)
(ƛ = lambda)
Wavelength is the distance between two adjacent wave crests/troughs
It is measured in metres (m) or nanometres (nm)
What is Frequency? (f)
Frequency is the number of waves that pass a fixed point in one unit of time (e.g. one second)
It is measured in hertz (Hz)
What is Wave number?
Wave number is the reciprocal of wavelength
( Wave number = 1 / wavelength)
What is Ionising radiation?
Ionising radiation is radiation that has energy equivalent to or above an atoms ionisation energy. This causes the atom to be ionised
NOTE: Ionised atoms lose electrons, it can be harmful
What do Rods and Cones do?
Rods and cones in the retina of the eye make light visible.
NOTE: Rods detect light, Cone cells detect colour
What is a Photon?
A photon is a subatomic particle. It is a massless, chargeless packet of energy with a specific wavelength, that travels at the speed of light
NOTE: The wavelength depends on the type of radiation
What is Avogadro’s constant? (L)
Avogadro’s constant (L) is the number of atoms in one mole of a substance
NOTE: The value of Avogadro’s constant (and plancks constant (h) ) can be found on DB page 20
What is a Quantum number? ‘n’
A quantum number is the number given to each energy level in an atom
e.g. The first energy level has the number n=1
What is the Ground state of an atom?
The ground state of an atom is the state where the atom has the least energy
What is the Excited state of an atom?
The excited state of an atom is any state with an energy greater than the ground state
e.g. If an electron was promoted to a higher energy level
What is Spectroscopy?
Spectroscopy is the analysis of the interaction between matter and any part of the electromagnetic spectrum
What is Refraction?
Refraction is the bending of light as it passes from one medium to another
e.g. As white light passes from air to glass (a denser medium)
What is the Atomic Emission Spectrum?
The atomic emission spectrum uses high temperatures to produce a series of coloured lines at different wavelengths on a dark background. The lines correspond to wavelengths of photons which were emitted when electrons drop energy level(s) and emit photon(s).
NOTE: It is not a continous spectrum
This is used to identify elements in a sample
What is the Atomic Absorption Spectrum?
The atomic absorption spectrum uses a beam of radiation to produce a continous spectrum showing dark bands. These bands correspond to the wavelengths of photons which were absorbed by atoms. The absorption of photons causes electrons to be promoted to higher energy levels.
What is the Lyman series?
A lyman line is seen when an electron drops from an excited state to its ground state (n=1)
This type of transition will emit a photon seen in the UV section of the spectrum
What is the Balmer series?
A balmer line is seen when an electron drops to the second energy level (n=2)
This type of transition will emit a photon seen in the Visible section of the spectrum
What is the Paschen series?
A paschen line is seen when an electron drops to the third energy level (n=3)
This type of transition will emit a photon seen in the Infared section of the spectrum
