This is class notes for the first year/AS chemistry. It covers the first chapter of physical chemistry - atomic structure including:
Fundamental physics
Mass number, atomic number and isotopes
The arrangement of electrons
The mass spectrometer
Ionisation energy
Fundamental particles
Developing ideas of the atom
• Greek philosophers had a model where matter was made up of a continuous substance making 4
elements – air, earth, fire and water.
• The fact matter was made up of individual atoms wasn’t taken seriously until another 2000
years.
• Alchemists built up a lot of evidence about how substances change and combine – trying to turn
metals into gold.
• 1661 – Robert Boyle proposed that some substances couldn’t be made simpler – chemical
elements.
• 1803 – Henri Becquerel discovered radioactivity, showing particles could come from inside the
atom, so it wasn’t indivisible.
• 1804 – J.J Thompson discovered the electron, the first sub-atomic particle to be discovered. He
showed electrons were negatively charged and were the same for all elements.
• As electrons were negative but atoms were neutral, there had to be a source of positive charge.
• Electrons were much lighter than the atom, so something had to be making up the rest of the
mass.
• J.J Thompson suggested the plum pudding model.
• 1911 – Ernest Rutherford and his team found that most of the mass and all the positive charge
was in a tiny central nucleus.
• It’s been known that atoms are made up of sub-atomic particles for years – the full picture in still
being built up in “atom smashers”. E.g., at CERN.
Sub-atomic particles
• Protons, neutrons and electrons.
• Protons and neutrons form the nucleus and are nucleons.
• Electrons surround the nucleus
Property Proton p Neutron n Electron e
Mass (kg) 1.673x10-27 1.675x10-27 0.9x10-30
-19
Charge (C) +1.602x10 0 -1.602x10-19
• The numbers are very small, so in practise relative masses and charges are used:
Property Proton p Neutron n Electron e
Relative mass 1 0 1/1840
Relative charge +1 0 -1
• In a neutral atom, the number of protons and electrons are equal.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller isobelcotton. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £2.99. You're not tied to anything after your purchase.
