Usethelewisstructuretodeterminethegeneral

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: rackets around all atoms and the charge in upper right corner. CHEM121 Exam 2 Study Guide Lewis structures for ternary oxyacids – A ternary oxyacid is a molecule that consists of H, O, and one other element. (Know that the formula for a ternary oxyacids starts with H.) – To draw the skeleton structure, write down the central atom, put the oxygens around it, then attach each hydrogen to a different oxygen. – Distribute valence electrons as usual. Lewis structures for hydrocarbons – hydrocarbon: consists of only C and H atoms – May contain several C atoms bonded to one another and surrounded by H atoms. Molecular Shapes and Polarity • Use the Lewis structure to determine the molecular shape and bond angle. • Use the Lewis structure to determine the general formula (A=central atom, X=# of outer atoms, E=# of lone pairs on central atom) and the steric number (SN=# of outer atoms + # of lone pairs on central atom). Know the following shapes and bond angles: ‐ AX2 and SN=2 → linear → 180° ∠ ‐ AX3 and SN=3→ trigonal planar → 120° ∠ ‐ AX4 and SN=4→ tetrahedral → 109.5° ∠ ‐ AX2E and SN=3→ bent or angular → <120° ∠ ‐ AX3E and SN=4→ trigonal pyramid → <109.5° ∠ ‐ AX2E2 and SN=4→ bent or angular → <109.5° ∠ • Use electronegativity to determine if a bond is polar or nonpolar covalent. • Be able to sketch a molecule after determining its shape and use dipole arrows to indicate the more electronegative atom in a polar covalent bond. • Use the 3D shape to determine if dipoles cancel or if there is an overall dipole to determine if a molecule is polar or nonpolar. page 2 of 4 Chapter 12: Liquids, Solids, and Intermolecular Forces Intermolecular Forces (IMF’s): attraction between 2 different molecules in a liquid or solid • Identify the type(s) of intermolecular force for a molecule as London/dispersion forces, dipole‐ dipole forces, hydrogen bonding, or ion‐diple forces. – Recognize that polar molecules experience London/dispersion forces a...
View Full Document

Ask a homework question - tutors are online