Transition Metals & Valence Electrons Chemistry 11 Transition Metals Do not form ions with noble gas configurations If they did, they would have to lose 4 or more electrons, and the energy needed to do this would be too high. These metals do form cations (“+” charged ion) with more than one charge (multi-valent) Electrons are first moved from the outer “s” and then inner “d” sublevels. Example 1: 25Mn (18Ar)4s23d5 Mn2+ loses 2 electrons from the “s” sublevel Mn2+ (18Ar)4s03d5 Example 2: 26Fe (18Ar)4s23d6 Fe2+ loses 2 electrons from the “s” sublevel Fe2+ (18Ar)4s03d6 Fe3+ (18Ar)4s03d5 Valence Electrons Are the electrons in the highest occupied energy level of an element’s atom. Are usually the only electrons used in the formation of chemical bonds. Note: Many of the similar chemical properties of elements in the same group (vertical column) are related to the number of “s” and “p” electrons in the highest occupied energy level. These electrons are valence electrons. Example 1: Sodium 11Na 1s22s22p63s1 Highest energy level = 3 Single “s” electron No “p” electrons for this element Na has 1 valence electron Example 2: Phosphorus 15P 1s22s22p63s2 3p3 Highest energy level = 3 Two “s” electrons Three “p” electrons 5 valence electrons Example 3: Potassium 19K Electron Configurations 1s22s22p63s2 3p6 4s1 Highest energy level = 4 1 valence electron Example 4: Carbon 6C Electron Configuration 1s22s22p2 Highest energy level = 2 4 valence electrons Example 5: Magnesium 12Mg Electron Configuration 1s22s22p63s2 Highest energy level = 3 2 valence electrons Example 6: Oxygen 8O Electron Configuration 1s22s22p4 Highest energy level = 3 6 valence electrons Electron Configurations & Periodicity Of the 3 subatomic particles, the electron plays the greatest role in determining the physical and chemical properties of an element. There is a relationship between the electron configuration of elements and their arrangement in the table.