electrons, AAS, AES, MS

Question 1

ground state

Answer 1

when electron is at its lowest possible energy levels

Question 2

how electrons jump

Answer 2

atoms absorb energy, electron around nucleus gain this extra energy and move up to higher energy levels.

energy levels are discreet. electrons cannot exist between energy levels, therefore amount of energy absorbed = difference in one energy level and another.

amount of energy absorbed by any sample of one element is the same

Question 3

excited state

Answer 3

an atom in which electrons occupy higher energy levels than the lowest possible energy levels.
as it moves back to ground state, emits light

Question 4

emission spectroscopy

Answer 4

absorption and emission of light help identify element
process of analysing light emitted by electron as it return to ground state

spectroscope: takes emitted light and separates it into its component wavelengths to produce a line emission spectrum.

sample to analysed is heated to much higher temperatures, and light emitted is passed through a prism. the prism disperses light into its component colours. the monochromatic allows single wavelengths to pass at a time, then spectra is recorded

fingerprint

Question 5

atomic absorption spectroscopy

Answer 5

uses absorption of light by electrons to measure how much of an element is present. used AAS

1. element analysed is determined: there could be many element in a sample but we need to focus on one. thus the lamp is made of the same element being tested. current passes through gaseous sample of element in l’amo and emits light. has unique wavelengths to other elements
2. vaporised: changing substances in sample to atoms. when light passes through, only the element being tested will absorb the light because it has the same energy levels as atoms that emitted light from lamp.
3. detection: light passed through sample enters monochromator-> selects one wavelength of light for analysis by detector-> measures intensity of light and turns it into a number.

compared to known samples by constricting a calibration curve.

Question 6

absorbance value

Answer 6

measure of amount of light that passed through sample without being absorbed, lets you know concentration

Question 7

mass spectrometry

Answer 7

based on different masses of atoms in sample

determine what elements are present in a sample or what isotope and their abundance in a sample.

determine isotopic composition of an element.

Question 8

method of mass spectrometry

Answer 8

1. ionisation: sample is bombarded with high energy electrons/ UV LIGHT.
   removes valence electrons leaving atom with positive charge
   does this with ALL atoms.
2. acceleration: cations accelerated through electrical field at very high speeds.
3. deflection: pass through a magnetic field where they undergo deflection according to their mass. ions separated according to mass and charge
   lighter= more deflection
4. detection: detectors measure amount of ions that strike them
   graphed in a mass spectrum.

Question 9

AAAS Light pulsation

Answer 9

light from the lamp is pulsed so that the detector can distinguish it from the light emitted by the flame containing the sample. finds extent of lamp light being absorbed and to what extent

Question 10

example of mass spectrometry

Answer 10

Astronomers use mass spectrometry to determine the elements and isotopes found in the solar wind.

Question 11

example of AAS

Answer 11

used in agriculture, mining, industry, hospitals and chemical laboratories

can be used to identify the presence of pollutants in the air,

Question 12

example of AES

Answer 12

One use of this technique is to identify the elements present in distant stars