Atomic Structure Flashcards
(31 cards)
What are energy/electron levels?
Fixed distances from the nucleus where an electron is found.
When the amount of energy that the atom experiences changes…
the electron structure changes.
What happens when an atom absorbs energy.
Electrons move from a lower energy level to a higher one. Once they had reached the higher level, they drop back down to a lower level.
What happens when the electron drops to a lower energy level?
The electron emits light.
Does every element emit the same colours?
No. Atoms of different elements absorb and emit certain wavelengths.
What is an absorption spectrum?
A spectrum that shows what happens when an atom absorbs certain frequencies of light. The dark stripes represent the light being absorbed.
What is an emission spectrum?
A spectrum that shows the frequencies that are emitted.
What is atomic absorption spectroscopy?
A technique that is used to determine the concentration of different elements in a solution.
How does AAS work?
This technique involves focusing light of a specific wavelength on atoms in a solution. Then it measures the amount of light that is absorbed.
What is absorbance?
The measurement of light that is absorbed by a substance.
What is an isotope?
An atom of an element that has a different number of neutrons. They have the same chemical properties but different physical properties.
What is the relative atomic mass?
The average mass of its atoms, compared to 1/12 of the mass of a carbon atom.
What is the relative atomic mass calculated from?
The mass numbers of the element’s isotopes and the abundance of these isotopes.
What is the formula for relative atomic mass?
Total mass of atoms/Total number of atoms
What is mass spectrometry?
An analytical technique where ions are sorted on their mass to charge ratio.
Mass to charge ratio is equal to…
atomic mass of cation / charge of cation.
What is quantitative analysis?
Analysis to determine concentration of solutions.
What is qualitative analysis?
Analysis to identify elements in a solution.
What are the four steps to working a mass spectrometer?
- Vaporisation
- Ionisation
- Acceleration and Deflection
- Detection
How does vaporisation work?
The sample is sucked up into a glass chamber. As it passes a tiny tube called a nebulizer it forms a spray. Mist goes into a tube called a torch where it goes to a plasma.
How does ionisation work?
As the mist enters the plasma, the liquid evaporates and ions are left. The ions are focused using cones forming an ion beam.
How does acceleration and deflection work?
The ion beam is then accelerated through magnetic rods called quadrupole. The rods deflect one type of ion towards the detector. The other ions are wasted.
How does detection work?
The detector is called an electron multiplier. It counts each ion as it comes out of the rods and displays it on a mass spectrum.
What is the trend in metallic character on the periodic table?
From right to left shows a gradual change from non-metallic to metallic.
