Chapter 3: Bonding- Chem rxns involve the transfer of electrons, which are important non-nuclear constituents of an atomo Each electron may be described by a wave function whose magnitude varies from point to point in spaceo Schrodinger Wave Equation: Hψ = Eψ ψ= wave function, H= Hamiltonian operator,E= energy  Maximum = + Minimum = - Each point in space can be represented by spatial coordinates (x, y, z) Node: Point @ which the wave changes its phase- Generated as the amplitude of the wave changes from + to –- Wave functions for electrons of diffenergies can be described in terms of the # of nodes- If there are 0 nodes, there’s no change in sign and the wave function remains +o Electron cloud is spherically shaped S- orbitals- 1 nodeo Electron cloud is dumb-bell shaped P-orbitalso 3 identical p orbitals: px, py, pz Three p-wave functions that describe three diffplaces where an electron has the same E, so the p-orbitals are said to be degenerate.- 2 nodes= d-orbitals - Heisenberg Uncertainty Principle: the position and momentum of an electron cannot be simultaneously specified o Its only possible to determine the probability that an electron will be found @ a particular pt. relative to the nucleus o A charge cloud represents the region of space where we are most likely to find the electron in terms of the (x, y, z) coordinates. Charge clouds are orbitals- Orbitals w/ lower principle quantum #’s are more stable (lowerin E)o Means than an electron in a 1s-orbital is lower in E than an electron in a 2s-orbital, and so on B/c 2s electrons are found further from the nucleus and it takes more E to hold a 2s electron to the nucleus than to hold a 1s electron.- E levels represent the region in space where electrons are found relative to the nucleuso Diff E levels are associated w/ each type of electron shell, so there are diff types of orbitals:Chapter 3: Bonding 1s, 2s, 3s, 4s, etc. They are similar in shape, but differ in E (distance from nucleus)o Electronic Configuration: the description of the wayelectrons are distributed in the atomic orbitals of an element Shows type, quantum level, and # of electrons- Chem rxns involve the gain, loss, or transfer of electrons (particularly valence electrons)o Valence Electrons: those found in the outermost orbitals (furthest from nucleus) More weakly bound than electron in orbitals closer to the nucleus- The periodic table is arranged more or less by chem reactivity, using the # of electrons in the outermost shell of the element and the E of those valence electronso Elements are arranged according to their valence orbitals- Organometallic: molecules composed of a metal w/ 1+ attached C atoms- The electron config of each element is described by the order in which the various orbitals fill as the # of electrons increases for each element of the periodic table.o Each indiv orbital can hold no more than 2 electronso Electrons have the property of spin, associated w/ magnetic dipole Electrons spin in opposite directions (spin paired)o A single orbital containing 2 electrons= filled orbital If 2 electrons occupy 1 orbital, spin pairing is lower than if 2 electrons of the same spin are forced to occupy the same orbital.o Pauli Exclusion Principle: if there are several orbitals of equal E (such as all 3 2p- orbitals), each orbitals will fill w/ 1 electron before any orbital contains 2o Attempting to fill one orbital w/ 2 spin-paired electrons before filling the next orbital would require more E Electrons have like charges, and 2 electrons will repel if they are in the same orbital, so electrons “fill” empty orbitals first to conserve E Aufbau Principle: orbitals are filled w/ electrons in ascending order of orbital E untilall available electrons have been used - 1s2s2p3s3p4s3d4p, etc- Electrons in an element or in a bond b/w 2 atoms are assumed to reside in orbitals.o A bond occurs b/w 2 atoms, and the electrons in that bond are associated w/ a molecule, not a single atomo B/c bonds are found in molecules the orbitals used to form a bond in a molecule are different from the orbitals found in elemental atomso The nucleus is the convergence point of the tricoordiante system- A chem rxn b/w atoms or groups of atoms will usually producenew combos of atoms held together by chemical bonds.Chapter 3: Bondingo Resulting bonds b/w atoms is composed of 2 electronso Covalent Bond: formed by mutual sharing of valenceelectrons b/w 2 atoms Sharing of electron density holds atoms 2gethero Ionic Bond: transfer of electrons from atom to another where atoms are held 2gether by electrostatic force Results in ions (+ and –) To participate in an ionic bond, an atom or group must be either electron rich or electronpoor and have a charge- Octet Rule: max of 8 electrons can occupy the valence shello Atoms like to have a noble config (having a filled outer electron chell) b/c they are particularly stable and therefore low in E and low in reactivityo There’s an energetic preference for transferring electrons to attain the noble gas config- During electron transfer processes, transfer of the (–) charged electron from Li leads to Li+ rather than Li- b/c Li+ is more stable (requires less E) to form.- E gained or lost for an atom is a measurable quantity o Ionization Potential: E required for the loss of electrons from an atomo Electron Affinity: E required for the gain of electrons into an atom- The bonds in molecules that contain C are usually formed by sharing electrons w/ one another atom in what’s known as a covalent bond, rather than a complete transfer of electronso Covalent bonds are more E favorable for certain atoms (elements) than ionic bonds.o Atoms in a molecule that contain C will react w/ another molecule to change the groups attached to C So, electron transfer is not w/ elemental C but rather a C-containing moleculeo The orbitals for atomic C are diff from the orbitals forcovalent C in a molecule C in the element is diff from the C in a molecule- When electrons are concentrated in orbitals on a single atom, the electrons are said to be “localized” on that atom.o When an atom is part of a covalent bond, however, it shares electrons w/ the other atom The electrons in the bond aren’t localized on one atom, but rather are shared by both atoms and concentrated b/w the atomso In a molecule, the electrons reside in diff orbitals are known as molecular