2. Elements and the Periodic Table Unit 2 Lesson 4

3. Science Journal Be sure to write to have your journals out and ready. Be sure to use today date Label Unit 2 Lesson 4

4. What is the PERIODIC TABLE? oShows all known elements in the universe. oOrganizes the elements by chemical properties.

5. I am Dmitri Mendeleev! I made the PERIODIC TABLE !

6. Dmitri Mendeleev http://science.howst uffworks.com/period ic-table-videos- playlist.htm http://science.howst uffworks.com/period ic-table-videos- playlist.htm 1834 - 1907 In 1869 he published a table of the elements organized by increasing atomic mass.

7. Elements known at this time

8. Both Mendeleev arranged the elements in order of increasing atomic mass. Both left vacant spaces where unknown elements should fit. Mendeleev called the “father of the modern periodic table”

9. stated that if the atomic weight of an element caused it to be placed in the wrong group, then the weight must be wrong. (He corrected the atomic masses of Be, In, and U) was so confident in his table that he used it to predict the physical properties of three elements that were yet unknown. Mendeleev...

10. After the discovery of these unknown elements between 1874 and 1885, and the fact that Mendeleev’s predictions for Sc, Ga, and Ge were amazingly close to the actual values, his table was generally accepted.

11. How do you read the PERIODIC TABLE?

12. What is the ATOMIC NUMBER? oThe number of protons found in the nucleus of an atom Or oThe number of electrons surrounding the nucleus of an atom.

13. What is the SYMBOL? oAn abbreviation of the element name.

14. What is the ATOMIC WEIGHT? oThe number of protons and neutrons in the nucleus of an atom.

15. How do I find the number of protons, electrons, and neutrons in an element using the periodic table? o# of PROTONS = ATOMIC NUMBER o# of ELECTRONS = ATOMIC NUMBER o# of NEUTRONS = ATOMIC _ ATOMIC WEIGHT NUMBER

16. Questions Finish the week with a Fun Video about the Periodic table http://youtu.be/zUDDiWtFtEM