CHEM 230 EXAM 1| 72 QUESTIONS | WITH COMPLETE SOLUTIONS

Organic Chemistry correct answer: the study of the compounds of carbon Electronegativity correct answer: A measure of the force of an atom's attraction for the electrons it shares in a chemical bond with another atom -increases from left to right -increases from bottom to top Difference between EN < 0.5 correct answer: Nonpolar covalent; two nonmetals or a nonmetal and a metalloid 0.5<Difference between EN>1.9 correct answer: Polar covalent; two nonmetals or a nonmetal and a metalloid Difference between EN > 1.9 correct answer: Ionic; metal and nonmetal Covalent bond correct answer: Forms when electron pairs are shared between two atoms whose difference in electronegativity is 1.9 or less Polar covalent bond correct answer: The more electronegative atom has a partial negative charge, indicated by the 8- The less electronegative atom has a partial positive charge, indicated by the symbol 8+ In neutral molecules containing C, H, N, O, and halogen correct answer: -Hydrogen has one bond -Carbon has 4 bonds and no unshared electrons -Nitrogen has 3 bonds and 1 unshared pair of electrons -Oxygen has 2 bonds and 2 unshared pairs of electrons -Halogen has 1 bond and 3 unshared pairs of elecrons Formal charge correct answer: The charge of an atom in a molecule or polyatomic ion VSEPR correct answer: Atoms are surrounded by regions of electron density Regions of electron density repel each other A molecule is polar if: correct answer: -It has polar bonds and -The vector sum of its bond dipoles is zero (the dipoles cancel each other) Resonance correct answer: A way to describe molecules and ions for which no single Lewis structure provides a truly accurate representation