Periodic Classification of Elements
Periodic Classification of Elements Classification of Elements according to electron configuration ( type of subshell being filled) *valence electrons –outer electrons of atom which are those involved in chemical bonding ; accounts for similarities in chemical behavior among elemens within each of this groups * Representative elements/ Main Group elements * Group 1A-7A * Incompletely filled s/ p subshells Display a wide range of physical and chemical properties * Most reactive and most predictable with respect to periodic properties * most abundant elements on the earth, in the solar system, and in the universe * Group number equals the number of electrons in the highest / outermost energy level H 1s1| Li 2s1| Na 3s1| * Noble Gases * Group 8A * Completely filled p subshell (exc. He) * Great stability * Except krypton and xenon, elements in noble gases are totally inert chemically * The noble gases are all found in minute quantities in the atmosphere, and are isolated by fractional distillation of liquid air. helium| 1s2| neon| [He]2s22p6| argon| [Ne]3s23p6| * Transition Metals * Group 1B and 3B-8B * Incompletely filled d subshells * Readily produce cations * ductile and malleable, and conduct electricity and heat * exhibit several common oxidation states * Less predictable properties * 2B (Zinc, Mercury etc.
)- neither representative elements nor transition metals * Transition metal compounds are paramagnetic when they have one or more unpaired d electrons. Sc 4s23d1| Ti 4s23d2| V 4s23d3| * Inner Transition Metals Lanthanides/rare earth series- Follow lanthanum
Actinides- follow actinium; most of these elements are not found in nature but have been synthesized * Incompletely filled f subshells * Cerium: 1s22s22p63s23p64s23d104p65s24d105p66s24f2 Praseodymium:1s22s22p63s23p64s23d104p65s24d105p66s24f3 Electron Configurations of Cations and Anions Ions derived from Representative Elements Cation- electrons removed Anion- electrons added Isoelectronic – ions or atoms and ions that have the same number of electrons, and hence the same ground state electron configuration Cations derived from transition Metals Prepared By: Monina Te