CH 220 1st Edition Lecture 2 Outline of Current Lecture I. Electron configurationsII. Types of bonding in compoundsIII. Lewis symbols of elements & Lewis structuresIV. Shapes of moleculesV. HybridizationCurrent Lecture I. Electron configurationsa. In neutral atoms the number of protons is equal to the number of electronsb. Valence electrons are involved in chemical bonding & reactions, as well as achieving a noble gas configurationc. Core electrons are not involved in chemical bonding or reactionsd. Atoms are more stable in compounds that as isolated atomse. The metals lose electrons from their valence shellf. Non-metals gain electrons to complete their valence shellII. Types of bonding in compoundsa. Organic chemistry focuses on nonmetal-nonmetal bonding, known as covalent bondingb. Covalently bonded compounds share electrons to achieve their octetc. Hydrogen is the exception – as it wants to complete its duetd. Na+ is a cation and is isoelectronic with Ne (it loses an electron so that it has the same amount of electrons as Ne)e. Cl- is an anion and is isoelectronic with Ar (it gains an electron so that it has the same amount of electrons as Ar)f. In a covalent bond, the nuclei are attracted to the electron density between atoms, which forms a directional bondg. Bond energy is the same to make a bond as it is to break a bondIII. Lewis symbols of elementsa. Bars represent bonded pairsb. Dots represent lone valence electrons that are non-bondingc. Methane is the smallest organic moleculed. Examples of the amount of bonds and lone pairs are shown below:These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.4th period 5th period 6th period 7th period 8th period4 bonds 3 bonds 2 bonds 1 bond 0 bonds 0 lone pair 1 lone pair 2 lone pairs 3 lone pairs 4 lone pairsCarbon Nitrogen Oxygen Fluorine NeonIV. Shapes of moleculesa. The directional nature of bonds dictates the shape of molecules and influences the reactivity of the moleculeb. VSEPR model – Valence Shell Electron Pair RepulsionThe sticks are in the plane, the dashed line is going behind and the wedge is coming out of the plane toward youc. Atoms that obey the octet rule can only have 2, 3, or 4 electron regions. The electron regions around atoms repel each other and they get as far away from each other as they can while still being tethered (attracted).V. Hybridizations- and p-orbitals form to make hybrid orbitalsHybrid orbitals are used for sigma bonds and lone pairsPure p orbitals are used for pi bondsWhen an s orbital hybridizes with one p orbital, we end up with 2 electron regions (sp) and the hybrid is 50% s and 50% p – the resulting bond angle is 180When an s orbital hybridizes with two p orbitals, we end up with 3 electron regions (sp2) and the hybrid is 33% s and 66% p – the resulting bond angle is 120When an s orbital hybridizes with all three p orbitals, we end up with 4 electron regions (sp3) and the hybrid is 25% s and 75% p – the resulting bond angle is