Chemistry Chapter 3 NotesI. Valence ElectronsA. Core Electrons1.Sublevels that are full are generally very stable and closer to the nucleusa) This means that electrons can neither be added or removed2.Only the outmost s sublevel can give up electrons when it is filled because it is really high in energya) Also only has 2 electrons3.Electrons in filled sublevels (other than s) are called core electronsB. Valence Electrons1. High energy electrons used in chemical bondinga) Found in the outer s sublevel and partially filled sublevels2. Occupy the valence orbitalsa) Can be shared with other atoms to produce bonds3. Given as the Valence Electron Configurationa) Electron configurations vary periodically, part of why chemical properties are periodic in the table to begin with4. Valence Orbitals are used to accept electrons from other atomsC. Configurations1. Electrons in filled d sublevels aren’t valence electronsII. Shielding and Effective Nuclear ChargeA. Shielding1.Valence electrons aren’t exposed to the full positive nuclear charge because they’re shielded by the core electrons2.The nuclear charge that is actually experiences by a valence electron is called the Effective Nuclear Chargea) Equal to: Charge of the nucleus (Z) – portion sheilded by other electrons (σ)B. Effective Nuclear Charge1.Z increases as protons are added, but σ increases more slowly because extra valence electrons don’t sheild a) Zeff is low for metals and high for nonmetal2.Each nodal plane in an orbital reduces electron density at the nucleus3.Shielding ability of electrons in a level decreases as their l number increasesa) Sheilding ability of electrons goes s > p > d > fIII. Relative Sizes of AtomsA. Relative Atomic Size1. Size of atoms depends on two factorsa) N quantum number: avaerage distance between an electron & nucleus. Constant within a period, changes down a groupb) Zeff: increases going across a periodIV. Orbital EnergyV. Ionization EnergyVI. ElectronegativityVII. Magnetic