Periodic Table Alkali Metals Group 1A Alkaline Metals Group 2A Transition Metals Group B Metalloids (7) Purple elements Halogens Group 7A Noble Gases Group 8A (orange)

Periodic Trends Atomic Radius 1/2 the distance between the nuclei of 2 like atoms in a diatomic molecule Increases from top to bottom Adding more energy levels Decreases from left to right More electrons and protons on the same energy level, so the attraction is greater…atom is pulled tighter together

Ionic Radius Increases from top to bottom Cations decreasesAnions decreases 1/2 dist. between the nuclei of 2 ions ex) Na +, O -2

Ionization Energy Decreases from top to bottom Increases from left to right The energy needed to remove an electron from a gaseous atom Na --> Na + + e - Adding more energy levels, so outermost electron is farther from nucleus. There is less attraction, so it takes less energy to remove it Atoms are smaller and the electrons are more attracted to the nucleus, so it takes more energy to remove an electron

1 st Ionization Energy The energy needed to remove the first outermost electron from a gaseous atom Same trends as Ionization energy 2 nd Ionization Energy The energy needed to remove the second outermost electron from a gaseous atom Value is greater than 1 st ionization energy e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

Shielding Effect Increases from top to bottom Constant from left to right The electrons in inner energy levels tend to push electrons in outer energy levels away from the nucleus Outermost electron is farther from nucleus There are more electrons and more energy levels to shield the attraction of the nucleus

Electronegativity Decreases from top to bottom Increases from left to right The tendency for an atom to attract an electron when they are chemically combined with atoms of another elements Outermost electron is farther from nucleus Attraction of electrons is less, so the atom is less likely to attract other electrons Atoms are smaller and the electrons are more attracted to the nucleus, so it is more likely to attract an electron from another atom

Ionic Radius vs. Atomic Radius Cations lose electrons, so they are smaller than its atom Anions gain electrons, so they are larger than its atom

Nuclear Charge Increases from top to bottom Increases from left to right The charge felt by the valence electrons after you have taken into account the number of shielding electrons that surround the nucleus More protons and electrons Increases with atomic number

Practice: 1. Which has a larger atomic radius in each group: a. K, Br, Ca, Cu b. Sb, Bi, N, P 2. Which has the larger ionization energy in each pair? a. Mg, Ba b. Li, C 3. Rank the following in order of increasing electronegativity. a. I, F, Cl b. Si, Al, Ar, Na a. K b. Bi a. Mg b. C a. I, Cl, F b. Na, Al, Si, Ar