Atomic Radius Ionization Energy Electronegativity Reactivity Periodic Trends Atomic Radius Ionization Energy Electronegativity Reactivity ½ distance between nuclei of identical atoms that are bonded Energy required to remove one electron Atom’s ability to add an electron.

Atomic Radii p.140 Period trends Trend to larger radii because proton pull is less on e- of same energy level … less p+ and less e- = bigger radii Group trends Trend to larger atoms because e- are added to NEXT energy level … farther away from nucleus. Larger Larger Display purple radii overhead sheet Which has largest atomic radii? Mg, Cl, Na, P, Na Which has largest atomic radii? Ca, Be, Ba, Sr? Ba Which has smallest atomic radii? Li, O, C, F ? F

88888 Octet rule P. 168 Chemical compounds tend to form so that each atom has an octet of electron in its highest occupied energy level. … ….atoms will try to get a group of 8 electrons in its outer orbit…. Either by gaining, losing, sharing ….electrons Draw pt and number groups ….explain give and take and share .

Do oxidation numbers here Ion = an atom or group of bonded atoms that have a + or – charge. If they have lost an electron they become postive……Na+ called cation If they have gained an electron they become negative……Cl- called anion. Do oxidation numbers here

Chlorine, nitrogen, calcium, copper, sulfur, sodium, Radii of Ions Positive Cations lost e- …. Lost therefore radii smaller Negative Anion gained e- …. gained therefore radii larger. Describe the ion radii of the following as increase or decrease. Chlorine, nitrogen, calcium, copper, sulfur, sodium,

Ionization energy p.143 energy required to remove one electron energy required to make it a cation Period trends Increases across period because more protons pull greater on e- in same energy level Group trends Increases going up group. Electrons are closer to nucleus so protons can pull electrons tighter. … therefore takes more energy to take an e-. Measured in k/joules

Ionization energy= energy required to remove one electron 2nd ionization = energy required to remove a 2nd electron 3rd ionization = energy required to remove a 3rd electron. “numbers will increase” Turn to p.146 in book “which would lose e- easier?” “Arrange the following in increasing ionization energy.” Li, O, C, K, Ne, F K,Li,C,O,F,Ne Which would least likely form? Sr2+, Al3+, K2+ K2+

Electronegativity ability to gain electrons ability to become an anion Period Ability to gain electrons increases across period Group Ability to gain electrons increases going up the Group… slightly Which element would gain e- easier? Br, I, Cl, F F Which element is most electronegative? C, N, O, Se, S

Reactivity Which would react easier with chlorine? Sodium or Potassium How about Sodium and Magnesium? What would happen if you put Lithium and Potassium in a beaker? What would happen if you then put in Bromine?