1. Organization of the Periodic Table

11. Why is the Periodic Table organized the way it is? • Thanks to Dmitri Mendeleev!!! • He put the chemicals and their properties on cards. • He put them in order of their atomic weight.

12. Why is the Periodic Table organized the way it is? • He found that some of the properties repeated periodically. • He predicted some holes in the periodic table predict three new elements and a variety of their properties like their density. • They were later discovered having similar properties to what Mendeleev predicted. Germanium, Gallium, Scandium

13. Making him the father of the Periodic Table!!!!

14. Organization Now • Henry Moseley organized it by Atomic number • The noble gases were discovered and added later with out messing up the organization.

15. Valence Electrons • Valence Electrons: The outer most electrons in the s and p orbitals. • Write the noble gas notations for all of the alkali metals. • This works for all the groups!!

16. Valence Electrons • How many valence electrons in • The halogens? • The boron group? • The alkaline earth metals? • The noble gases? • Chemical reaction happen because of the valence electrons • This is why elements in the same group behave similarly

17. Periodic Trends!!! • Atomic Radii: half the distance between the nuclei of two atoms.

18. Atomic Radii The trend Why?

19. Ionization Energy • The energy required to remove an electron. • What do you think the trend is? • Why?

20. Ionization Energy

21. Electronegativity • The ability to attract an electron. • What do you think the trend is? • Why?

22. Electronegativity