2 Valence ElectronsValence electrons are the electrons that occupy the outside orbitals of the electron cloud.The highest energy level is equal to the period
3 Valence Electrons Group 1 has 1 valence electron Group 2 has 2 valence electronsGroups 3-12 (transition metals) varyGroup 13 has 3 valence electronsGroup 14 has 4 valence electronsGroup 15 has 5 valence electronsGroup 16 has 6 valence electronsGroup 17 has 7 valence electronsGroup 18 has 8 valence electrons
4 Formation of Ions Ionization – The formation of an ion Groups 1-14 elements make cationsThese ions ALWAYS have 0 valence electronsGroups elements make anionsThese ions ALWAYS have 8 valence electronsGroup 18 elements (noble gases) don’t make ions because they already have 8 valence electronsThe charge of an ion can be determined from the number of valence electrons1 valence e- makes a +1 charge because it had to lose 1 electron to equal zero6 valence e- makes a -2 charge because it had to gain 2 electrons to equal 84 valence e- makes either a +4 or a -4 charge, depending on the element
6 Properties of GroupsGroup 1 Alkali Metals: Most metallic and reactive groupform +1 cationsGroup 2 Alkaline Earth metals: Very reactive groupform +2 cationsBlock D Transition Metals: Semi-reactiveform cations with different chargesBlock F Lanthanides and Actinides: Radioactive and extremely heavy metalsGroup 16 Chalcogens: Very reactive and electronegativeform -2 anionsGroup 17 Halogens: Extremely reactive and electronegative groupform -1 anionsGroup 18 Noble Gases: Completely unreactive because of complete valence shell
7 Types of ElementsThere are 3 types of elements: metals, metalloids and nonmetals1) S, D and F block Metals: Malleable (can change shape without breaking), shiny, conducts electricity2) P Block Metalloids: Show both metallic and non- metallic character. Metalloids touch the staircase of the periodic table3) P Block Nonmetals: dull, brittle, and poor at conducting electricity because they hog electrons
8 HistoryMendeleev was the scientist responsible for seeing the pattern of properties of the elements in the periodic tablehe was the first to organize those elements into periods and groups.Elements within the same group have the same physical and chemical properties.When he organized his version of the table, there were holes in it because there were only 60 out of 110 known elements at the time. After he died, the holes were later filled by newly discovered elements, verifying what he knew to be correct:you can predict how an atom will behave by knowing where its atomic number falls on the periodic table.Periodic law – Both physical and chemical properties of the elements are functions of their atomic numbers.