atomic structure

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  • Created by: NicoleAD
  • Created on: 25-04-16 21:09
what is the structure of an atom in terms of particles?
protons and neutrons are located within the nucleus of an atom whilst the electrons are located in the orbits around the nucleus.
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what the relative atomic mass?
the average mass of atom of an element on a scale where carbon-12 is exactly 12.
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what is the mass number?
the mass number is the total number of protons and neutrons within the nucleus of an atom.
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what is the atomic number?
the atomic number is the number of protons in the nucleus. This also however tells us the number of electrons.
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what is an isotope?
different atomic forms of the same element with the same number of protons different number of neutrons.
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How does an ion form?
An ion forms by the loss or gain of an electron.
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What is the relative isotopic mass?
This is the mass of an atom of an isotope of an element on a scale where carbon-12 is exactly 12.
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Define relative molecular mass.
This is the average mass of a molecule on a scale where an atom of carbon-12 is exactly 12.
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How do you calculate relative atomic mass?
isotopic masses x percentages /100
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Explain electrospray ionisation.
The sample is dissolved in a polar solvent. Then is pushed through a nozzle at high pressure. High voltage is applied, this removes an electron from the particle. Ionised particles separate out from the solvent. Leaving a gas of positive ions.
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Explain acceleration.
positive ions are accelerated by the electric field, particles need to be positively charged in order to be accelerated by the electric field. Electric field supplies all ions with the same kinetic energy to all ions.
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Explain ion drift.
ions leave the electric field with constant speed and constant kinetic energy. ions with lower mass charge ratio drift at higher speeds.
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Explain detection.
Lower mass/charge ratio ions drift at higher speeds so reach the detector in less time.
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Define the first ionisation energy.
The amount of energy required to remove 1 electron from 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.
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State the three factors affecting ionisation energy.
1. nuclear charge 2. distance from nucleus 3.shielding
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How do you calculate the number of particles?
number of particles =number of moles x avogadros constant
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How to calculate the number of moles.
number of moles = mass of substance/ mr
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what is the ideal gas equation?
pV=nRT
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What is the theoretical yield?
It's the mass of product that should be formed in a chemical reaction.
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How do you calculate the percentage yield?
percentage yield = actual yield / theoretical yield x 100
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state 2 advantages of high atom economy
it makes more efficient use of raw materials and there is less waste to deal with
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what are the ethical advantages of a high atom economy
produce less waste so better for the environment. Raw materials are in limited supply so more efficient use means that they will last longer. High atom economy processes tend to be more sustainable.
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How to work out atom economy
Atom economy = molecular mass of desired product / the sum of molecular masses of all reactants x100
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Card 2

Front

what the relative atomic mass?

Back

the average mass of atom of an element on a scale where carbon-12 is exactly 12.

Card 3

Front

what is the mass number?

Back

Preview of the front of card 3

Card 4

Front

what is the atomic number?

Back

Preview of the front of card 4

Card 5

Front

what is an isotope?

Back

Preview of the front of card 5
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