Activity-Which is easier? Pg. 80Your time (seconds) Your time (seconds)RANDOM ORDER ROWS
Why is the PeriodicTable important to me? most useful tool to a chemist organizes lots of info. about all known elements
Pre-Periodic Table Chemistry … …was a mess!!! No organization of elements. Imagine going to a grocery store with no organization!! Difficult to find information. Chemistry didn’t make sense.
Dmitri Mendeleev: Father of the Table HOW HIS SOME WORKED… PROBLEMS… Put elements in rows He left blank spaces by increasing atomic for what he said were mass. undiscovered elements. (Turned Put elements in out he was right!) columns by the way He broke the pattern they reacted. of increasing atomic weight to keep similar reacting elements together.
The Current Periodic Table Mendeleev wasn’t too far off. Now the elements are put in rows by increasing ATOMIC NUMBER!!
Each square of periodic table incl: element’s atomic number= # of protons in its nucleus chemical symbol name atomic mass= avg. mass of all isotopes of that element 15.9994