Chem 333 1st Edition Lecture 1Outline of Last Lecture I. No previous outlineOutline of Current Lecture II. Atomic StructureIII. ElectronsIV. Octet Rule Current LectureI. Atomic Structurea. Atomi. Components1. Nucleusa. Protons and neutrons2. Electron cloudII. Electronsa. Electrons cannot move freely i. They move in shells or energy levelsii. Each shell is broken into subshells1. S,p,d, and f2. Shell 1 = 1s3. Shell 2 = (2s) 2px 2py 2pz4. Shell 3 = (3s) 3px 3py 3pz (5 d orbitals)b. Each shell contains 2n^2 electronsi. N = number of shellc. Electrons are grouped into orbitalsi. Regions of space that only hold 2 electronsd. Electron configurationi. Description of electrons in orbitalse. Ground state configuration i. Lowest energy level1. Determined by these rulesa. Aufbau principles (“build up”)1. Fill lowest orbitals first2. 1s – 2s – 2p – 3s …b. Pauli exclusion principle 1. Only two electrons per orbital2. Opposite spinsc. Hunds Rule1. Add 1 electron to each orbital equal in energy first then add the second electron to each orbital 2. Minimizes electron repulsionf. Valence electronsi. Outer shell electrons involved in bondingii. Gives an atom its chemical propertiesiii. Examples1. Carbon – 4 valence electrons2. Nitrogen – 5 valence electrong. Octet Rulei. Atoms want 8 electronsii. Chemical bonds form in an attempt to complete the octet throughsharing electrons between atoms iii. Complete octet by1. Lose or gain electrons become ionic a. Na – wants to lose one electron so it becomes Na^+= filled octet2. Share electrons with 1 or more atomsa. Forms covalent bondsb. H- and –H share electrons to form a covalent bond and become