Chemical elements - some substance could not be made simpler.
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What did John Dalton discover?
Atoms of the same element have the same mass. Atoms cannot be broken down.
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Who discovered radioactivity?
Henri Becquerel.
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Who made up the plum pudding model?
JJ Thompson
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What did Ernest Rutherford discover?
Most of the mass and all positive charge came from a nucleus.
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What relative charge does a proton have?
+1
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What relative mass does an electron have?
1/1840
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What is the mass number?
Number of protons + number of neutrons.
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What makes up most of the mass of an atom?
Protons and nuetrons.
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What is the atomic number?
The number of protons in the nucleus.
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Why most atoms neutral?
The number of protons is equal to the number of electrons so the charges balance out.
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Do atoms of the same element have the same atomic number?
Yes.
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What is an isotope?
An atom witht eh same number of protons and electrons but a different number of neutrons.
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What do isotopes of the same element have the same chemical properties?
They have the same number of electrons as eachother.
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What does a mass spectrometer do?
Determine the relative atomic mass of a substance.
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What happens in a time of flight mass spectrometer?
A sample is dissolved in a solvent and forced through a tiny hole which produces positively charged ions. Then positive ions are attracted towards a negative plate and accelerate towards it. Ions pass through a hole in the negative plate.
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How to work out atomic mass of isotopes:
Multiply each atomic mass by their abundance and divide by the total abundance.
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