1. What is meant by the periodic repetition of properties of elements?
2. Mendeleev’s table of elements built upon the work of previous scientists.
a) What information was available to Mendeleev when he constructed a periodic table?
b) Mendeleev used the formulae of chlorides and hydrides to help him group the elements. What pattern did he observe in the formulae of chlorides and hydrides of group 1 metals?
c) How did you use similar patterns to place elements in different groups? Give two examples.
d) What other information might have been useful to you to help sort the element cards?
3. Look at the group I elements in your Periodic Table. Does each group of three follow the law of triads observed by Johann Dobereiner? Explain why or why not.
4. How has atomic weight helped to organise the elements in your Periodic Table? Give some examples.
5. How does atomic number differ from atomic weight?
6. If Mendeleev had known atomic number would it have been easier to organise the elements? Explain why or why not.
7. Why is the arrangement of elements into the modern Periodic Table in order of atomic number rather than atomic weight?