CH2 Chemistry - Mass of Atoms

From today's lesson you need be able to do the following:

• State what an atom’s atomic number is.
• State what an atom’s mass number is.
• Know what the relative masses of protons, neutrons and electrons are.
• Explain what an isotope is.

And could also:

• Describe and explain the physical and chemical properties of isotopes of the same element. 

Watch this useful revision video:

Then watch this one, about Mendeleev's construction of the periodic table based on the Atomic Weights of the elements known at the time - there will be a couple of quick test questions on this on Wednesday.