AP Notes Chapter 7 Electron Configuration Magnetism Periodic Trends

Aufbau Principle Aufbau is German for building up. Aufbau is German for building up. As the protons are added one by one, the electrons fill up hydrogen-like orbitals. As the protons are added one by one, the electrons fill up hydrogen-like orbitals. e- are added to atoms into the lowest energy level & sub-level available e- are added to atoms into the lowest energy level & sub-level available Fill up in order of energy levels. Fill up in order of energy levels.

Details Valence electrons- the electrons in the outermost energy levels (not d). Valence electrons- the electrons in the outermost energy levels (not d). Core electrons- the inner electrons. Core electrons- the inner electrons. Hund’s Rule- The lowest energy configuration for an atom is the one that will have the maximum number of unpaired electrons in the orbital. Hund’s Rule- The lowest energy configuration for an atom is the one that will have the maximum number of unpaired electrons in the orbital. C 1s 2 2s 2 2p 2 C 1s 2 2s 2 2p 2

max e - n = 1 max e - n = 1

max e - n = 1 s 2 n = 2 max e - n = 1 s 2 n = 2

max e - n = 1 s 2 n = 2 s 2 8 p 6 n = 3 max e - n = 1 s 2 n = 2 s 2 8 p 6 n = 3

max e - = 2n 2 max e - = 2n 2 n = 1 s 2 n = 2 s 2 8 p 6 n = 3 s 2 p 6 18 d 10 n = 1 s 2 n = 2 s 2 8 p 6 n = 3 s 2 p 6 18 d 10

Pauli Exclusion Principle nlm l s / / / / / /2 nlm l s / / / / / / / / / / / / / /2 Orbital 1S 2s 2p

Pauli Exclusion Principle No 2 e - in same atom can have the same set of four quantum numbers No 2 e - in same atom can have the same set of four quantum numbers

Quantum #s ___, ___, ___, ___ n m l m s Electron Probability Space & Quantum Numbers

Spin QN = m s (s) spin of e - on own axis

Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f He with 2 electrons Ne with 10 electrons Ar with 18 electrons

Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2 electrons 2s 2 4 2p 6 3s p 6 4s d 10 4p 6 5s d 10 5p 6 6s 2 56

7s 7p... 6s 6p 6d... 5s 5p 5d 5f... 4s 4p 4d 4f 3s 3p 3d 2s 2p 1s

Details Elements in the same column have the same electron configuration. Elements in the same column have the same electron configuration. Put in columns because of similar properties. Put in columns because of similar properties. Similar properties because of electron configuration. Similar properties because of electron configuration. Noble gases have filled energy levels. Noble gases have filled energy levels. Transition metals are filling the d orbitals Transition metals are filling the d orbitals

Examples 3 Li 6C6C6C6C 8O8O8O8O 19 K 24 Cr 29 Cu

Exceptions Ti = [Ar] 4s 2 3d 2 Ti = [Ar] 4s 2 3d 2 V = [Ar] 4s 2 3d 3 V = [Ar] 4s 2 3d 3 Cr = [Ar] 4s 1 3d 5 Cr = [Ar] 4s 1 3d 5 Mn = [Ar] 4s 2 3d 5 Mn = [Ar] 4s 2 3d 5 Half filled orbitals. Half filled orbitals. Scientists aren’t sure of why it happens Scientists aren’t sure of why it happens same for Cu [Ar] 4s 1 3d 10 same for Cu [Ar] 4s 1 3d 10

All atoms want a noble gas or pseudo noble gas configuration Atoms with full or half-full sub-levels are particularly stable

Gain or loss of e - produces ions Consider: Zn 2+, Ag +, Cu 2+

Energy Level Diagram 3d __ __ __ __ __ 4s __ 3p __ __ __ 3s __ 2p __ __ __ 2s __ 1s __ 3d __ __ __ __ __ 4s __ 3p __ __ __ 3s __ 2p __ __ __ 2s __ 1s __

Gain or loss of e - produces ions Consider: Zn 2+, Ag +, Cu 2+ Ions with full or half-full sub-levels are particularly stable

Gain or loss of e - produces ions Consider: Na +, Ne, F -

Energy Level Diagram 3d __ __ __ __ __ 4s __ 3p __ __ __ 3s __ 2p __ __ __ 2s __ 1s __ 3d __ __ __ __ __ 4s __ 3p __ __ __ 3s __ 2p __ __ __ 2s __ 1s __

Gain or loss of e - produces ions Consider: Na +, Ne, F - Chemical species with the same e - configuration are ISOELECTRONIC Chemical species with the same e - configuration are ISOELECTRONIC

Diamagnetic - Slightly repelled by a strong magnet (moments counter each other e- are paired) Paramagnetic – Attracted to magnetic field (moments not aligned e- are unpaired ) Ferromagnetic – Materials retain a magnetic field if one has been induced (moments are aligned e- are unpaired)

Trends of the Periodic Table

Triplet Trends Organize trends Organize trends Use only increasing properties Use only increasing properties Learn the diagonal NOT the two vectors that make up the diagonal….. Learn the diagonal NOT the two vectors that make up the diagonal….. You can always recreate the two vectors so you have less to learn or memorize You can always recreate the two vectors so you have less to learn or memorize

Atomic Number Increases to the right Increases to the right Increases down Increases down

Atomic Mass Increases to the right Increases to the right Increases down Increases down

Nuclear Charge Increases to the right Increases to the right Increases down Increases down

Atomic Radius Is taken as the covalent radius for non-metallic elements and as the metallic radius for metals Is taken as the covalent radius for non-metallic elements and as the metallic radius for metals

Atomic Radius Covalent radius is one-half the distance between the nuclei of two identical atoms that are singly bonded to one another. Covalent radius is one-half the distance between the nuclei of two identical atoms that are singly bonded to one another.

Atomic Radius Covalent radii for elements whose atoms do not bond to one another can be estimated by combining radii of those that do with the distances between unlike atoms in various molecules. Covalent radii for elements whose atoms do not bond to one another can be estimated by combining radii of those that do with the distances between unlike atoms in various molecules.

Atomic Radius Metallic radius is one-half the closest internuclear distance in a metallic crystal. Metallic radius is one-half the closest internuclear distance in a metallic crystal.

Atomic Radius

Ionic Radii Size

Overall Activity

Ionization Energy Is the energy required to remove the outermost electron from an atom or a positive ion in the ground state. Is the energy required to remove the outermost electron from an atom or a positive ion in the ground state.

First Ionization Energy Energy required to remove the first electron from a neutral atom. Energy required to remove the first electron from a neutral atom.

First Ionization Energy

Second Ionization Energy Energy needed to remove the outermost electron from a +1 ion. Energy needed to remove the outermost electron from a +1 ion. Energy needed to remove the second electron from a neutral atom. Energy needed to remove the second electron from a neutral atom.

Second Ionization Energy

Electron Affinity Energy released or absorbed when an electron is added to the valence level of a gas-phase atom. Energy released or absorbed when an electron is added to the valence level of a gas-phase atom.

Electron Affinity

Electronegativity Ability to bond & desire for electrons Ability to bond & desire for electrons