CHEM 281 Lecture 1: 3-APPENDIX STEREOCHEMISTRY CHEM 281 - 2016-3 Problem Set 3 - WEEK 4

which has more melting point- cyclopropane or propane?
the one which is more symmetrical has more m.p but i am confusedwhich one is more symmetrical..plzz tel!

Why is a polar group?

1. Nitrogen is more electronegative than hydrogen
2. The bonds are not symmetrical
3. Because hydrogen bonding takes places
4. Both a and b are correct

Question 56

What drives an atom to form a covalent bond: its nuclear charge or the need to have a filled outer shell?

A.its nuclear charge

B.its need to have a filled outer shell

C.both

D.neither

Question 57

Which of the following would be a negative ion with a single charge?

A.an atom with 11 protons and 12 electrons

B.an atom with 11 protons and 11 electrons

C.an atom with 12 protons and 11 electrons

D.an atom with 10 protons and 12 electrons

E.None of these

Question 58

Classify the following bonds as ionic, covalent, or neither (O, atomic number 8; F, atomic number 9; Na, atomic number 11; Cl, atomic number 17; U, atomic number 92)?. O with F.... Ca with Ci...Na with Na

A.covalent, ionic, covalent

B.ionic, covalent, neither

C.neither, ionic, covalent

D.covalent, ionic, neither

Question 59

How many valence electrons does bromine (Br, atomic no. = 35) have?

A. 1

B. 7

C.21

D.28

E. 35

Question 60

Consider the electron-dot geometries of PF5 and SF4. Which do you expect is the more polar compound?

A.The PF5 should be more polar because it has a greater number of fluorines.

B.The PF5 should be more polar because it is more symmetrical.

C.The SF4 should be more polar because it has a lone pair of electrons.

D.The SF4 should be more polar because it is less symmetrical.