Guided Questions

 Elements are the simpler substances (atoms) from which all other substances are made.

 Aristotle’s 5 th element was called “ether” and this was supposed to be the composition of heavenly bodies (the Gods).

 The goal of alchemy was to make gold!  Alchemists believed that any form of matter could be manufactured by varying the proportions of a few basic elements.

 Because alchemists wanted to make gold they mostly studied metals.

 Antoine Lavoisier is considered the father of modern chemistry as he performed numerous experiments in order to describe the chemical and physical properties of the elements.

 4 categories: metals, nonmetals, gases & earths  Lavoisier thought that light and heat (energy) were elements

 Every element has a different emission of spectral lines. Like fingerprints these line spectra served as a clear way to confirm the discovery of a new element

 Dimitri Meneleev is given credit for coming up with first plan for classifying the elements.  M. made cards for each element that included the element symbol and atomic mass. He then laid them out in rows and columns to look for patterns (inspired by solitaire)

 Mendeleev left gaps in the table for elements that hadn’t been discovered yet. He knew the gaps should be there based on predicted properties of the elements in specific columns.  All of the gaps that M. left have now been filled

 The modern periodic table is based on atomic number  This arrangement shows clearly repeating patterns in the physical and chemical properties of the elements