CHE 230 Exam 1 _Fall 2010 - Department of Chemistry - Illinois ...

1. Write out the ground state electron configuration for carbon. (5 pts) 1s 2 2s 2 2p 22. How many valence electrons does carbon have available? (5 pts) 43. What is the hybridization of carbon in methane, CH 4 ? (5 pts) sp 34. Would methane be considered to be a polar molecule (Y/N)? (5 pts) N5. Which combination of properties below best describes why carbon forms covalent bonds and NOT ionicbonds? (20 pts)a) High ionization potential and high electron affinityb) Low ionization potential and low electron affinityc) High ionization potential and low electron affinityd) Low ionization potential and high electron affinityC6. Write out the electron configuration for sodium ( 11 Na) and provide a brief explanation for why sodium canreadily lose an electron. (20 pts)11Na [1s 2 ] [2s 2 2p 5 ] [3s 1 ] - e -→ [1s 2 ] [2s 2 2p 6 ]closed shell configuration!!7. Write out the electron configuration for fluorine ( 9 F) and provide a brief explanation for why fluorine canreadily gain an electron. (20 pts)9F [1s 2 ] [2s 2 2p 5 ] + e -→ [1s 2 ] [2s 2 2p 6 ] closed shell configuration!!8. Consider the compound sodium fluoride (boiling point = +993 o C) and methane (boiling pt = -161 o C).Why do these molecules have such different boiling points? (40 pts)The difference in boiling point is attributed to the intermolecular forces in sodium fluorideversus methane. Sodium fluoride is a very polarized molecule. This polarization gives riseto a network of interaction that holds the molecules together. Methane is not polar and doeshave not the same forces in play.9. Draw reasonable Lewis structures for the following molecules (80 pts):C 2 H 2 N 3-N N NH 2 CS SO 2© 2010 Prof. S. R. Hitchcock, Department of Chemistry, Illinois State University, Normal, IL 61790-41601