CHEM H90 Lecture Notes - Lecture 9: Calcium Oxide, Lithium Oxide, Chemical Formula

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25 Apr 2017
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Outline: basic types of bonds, strong bonds, covalent. Ionic: metallic, weak bonds, hydrogen bonds, van der waals interactions, reference material, cartoon guide: chapter 3, context: 1. 7, 1. 8, 2. 3, context: 5. 2, 5. 7. Covalent bonds: loosely, the bonds between non-metals, electrons are shared between atoms, most common in molecules, classic example, h2, all homonuclear diatomics, such as o2, n2, usually covalent for organic molecules (e. g. ) methane, ch4. Weak bonds: not usually called chemical bonds, strongest are hydrogen bonds, crucial to all special properties of water. Octet rule: main-group ato(cid:373)s (cid:862)(cid:449)a(cid:374)t(cid:863) to (cid:272)lose their outer(cid:373)ost shells, (cid:449)hi(cid:272)h (cid:272)o(cid:374)tai(cid:374)s 8 ele(cid:272)tro(cid:374)s. If only a few valence electrons, get rid of them. If close to full, grab some electrons: for h, it"s a duet rule. It"s (cid:271)y itself i(cid:374) that first ro(cid:449) a(cid:374)d there"s o(cid:374)ly roo(cid:373) for t(cid:449)o. Common names for elemental ions: number of electrons is fixed, (cid:862)-ide(cid:863) i(cid:374) the (cid:374)a(cid:373)e of the (cid:272)o(cid:373)pou(cid:374)d, the halogens grab one electron, oxygen grabs two electrons, etc.