Dr. S. M. Condren Chapter 8 Electron Configuration and Periodicity
Dr. S. M. Condren Orbitals region of probability of finding an electron around the nucleus 5 types => s p d f g maximum of 2 electrons per orbital
Dr. S. M. Condren Pure Atomic Orbitals shape # of orbitals / energy level s spherical 1 p dumbbell 3 d complex 5 f very complex 7 gextremely complex 9
Dr. S. M. Condren Pauli Exclusion Principle
Dr. S. M. Condren Electronic Configurations The shorthand representation of the occupancy of the energy levels (shells and subshells) of an atom by electrons.
Dr. S. M. Condren Electronic Configuration shells=>energy levels subshells=>orbitals
Dr. S. M. Condren
Regions by Electron Type
Dr. S. M. Condren Electron Filling Order Diagram 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 7s 7p Start here
Dr. S. M. Condren Electronic Configuration H atom 1 electron 1s 1
Dr. S. M. Condren Electronic Configuration He atom 2 electrons 1s 2
Dr. S. M. Condren Electronic Configuration Li atom 3 electrons 1s 2, 2s 1
Dr. S. M. Condren Electronic Configuration Cl atom 17 electrons 1s 2, 2s 2, 2p 6, 3s 2, 3p 5
Dr. S. M. Condren Electronic Configuration As atom 33 electons 1s 2, 2s 2, 2p 6, 3s 2, 3p 6, 4s 2, 3d 10, 4p 3 or [Ar] 4s 2, 3d 10, 4p 3
Dr. S. M. Condren Mn: [Ar]4s 2 3d ? How many d electrons does Mn have? 4, 5, 6
Dr. S. M. Condren
Electronic Configuration negative ions add electron(s), 1 electron for each negative charge
Dr. S. M. Condren Electronic Configuration S -2 ion (16 + 2)electrons 1s 2, 2s 2, 2p 6, 3s 2, 3p 6
Dr. S. M. Condren Electronic Configuration positive ions remove electron(s), 1 electron for each positive charge
Dr. S. M. Condren Electronic Configuration Mg +2 ion (12-2)electrons 1s 2, 2s 2, 2p 6
Dr. S. M. Condren How many valence electrons are in Cl, [Ne]3s 2 3p 5 ? 2, 5, 7
Dr. S. M. Condren For Cl to achieve a noble gas configuration, it is more likely that electrons would be added electrons would be removed
Dr. S. M. Condren
Trends in the Periodic Table atomic radius ionic radius ionization energy electron affinity
Dr. S. M. Condren Atomic Radius decrease left to right across a period as nuclear charge increases, number of electrons increase; however, the nucleus acts as a unit charge while the electrons act independently, pulling electrons towards the nucleus, decreasing size
Dr. S. M. Condren Atomic Radius increase top to bottom down a group each additional electron “shell” shields the outer electrons from the nuclear charge Z eff = Z – S where Z eff => effective nuclear charge Z => nuclear charge, atomic number S => shielding constant
Dr. S. M. Condren Atomic Radius increases from upper right corner to the lower left corner
Dr. S. M. Condren Atomic Radius vs. Atomic Number
Dr. S. M. Condren Atomic Radius
Dr. S. M. Condren Ionic Radius same trends as for atomic radius positive ions smaller than atom negative ions larger than atom
Dr. S. M. Condren Ionic Radius Isoelectronic Series series of negative ions, noble gas atom, and positive ions with the same electronic confiuration size decreases as “positive charge” of the nucleus increases
Dr. S. M. Condren Ge is a semiconductor. If half of the Ge atoms of a sample of Ge are replaced with Ga atoms, with what element should the other half of the Ga atoms be replaced in order for this new compound to be isoelectronic with Ge? Sn, As, Se
Dr. S. M. Condren Ionization Energy energy necessary to remove an electron to form a positive ion low value for metals, electrons easily removed high value for non-metals, electrons difficult to remove increases from lower left corner of periodic table to the upper right corner
Dr. S. M. Condren Ionization Energies first ionization energy energy to remove first electron from an atom second ionization energy energy to remove second electron from a +1 ion etc.
Dr. S. M. Condren Ionization Energy vs. Atomic Number
Dr. S. M. Condren Electron Affinity energy released when an electron is added to an atom same trends as ionization energy, increases from lower left corner to the upper right corner metals have low “EA” nonmetals have high “EA”
Dr. S. M. Condren Magnetism Result of the spin of electrons diamagnetism - no unpaired electrons paramagnetism - one or more unpaired electrons ferromagentism - case of paramagnetism where the substance retains its magnetism
Dr. S. M. Condren Magnetism Paramagnetism Ferromagnetism Without applied field With applied field