CHEM 105 Chapter 5 Quiz

Question 1

metal and nonmetal atoms form ? bonds

Answer 1

ionic

Question 2

nonmetal and nonmetal atoms form ? bonds

Answer 2

covalent

Question 3

metal and metal atoms form ? bonds

Answer 3

metallic

Question 4

electronegativity ? down a period (L to R) and ? down a group (top to bottom)

Answer 4

increases down a period and decreases down a group

Question 5

? is the most EN element (4.0)

Answer 5

Fluorine

Question 6

? is the least EN element (0.7)

Answer 6

Francium

Question 7

ΔEN small (0-0.4)

Answer 7

covalent (nonpolar covalent if not 0)

Question 8

ΔEN = 0

Answer 8

pure covalent (equal sharing of the atoms in the bond)

Question 9

ΔEN intermediate (0.4-2.0)

Answer 9

polar covalent (unequal sharing of electrons b/w the atoms in the bond)

Question 10

ΔEN large (2.0+)

Answer 10

ionic

Question 11

dipole moment (μ)

Answer 11

a measure of bond polarity; directly proportional to the size of the partial charges (q) and directly proportional to the distance (r) between them
μ = qr
measured in Debyes (D)

Question 12

generally, the more electrons two atoms share and the larger the atoms are, the (smaller/larger) the dipole moment

Answer 12

larger

Question 13

percent ionic character

Answer 13

the percent of a bond’s measured dipole moment compared to what it would be if the electrons were completely transferred (indicates the degree to which to the electron is transferred)

Question 14

percent ionic character (decreases/increases) with ΔEN

Answer 14

increases

Question 15

steps to drawing Lewis structures

Answer 15

1. add up valence e-s
2. choose central atom (lower EN) and draw one bond to each terminal atom
3. fill in octet (or duet, in the case of H), for each terminal atom
4. add remaining e-s to central atom (if any)
5. check the numbers and the octets

Question 16

resonance

Answer 16

used when two or more valid Lewis structures can be drawn for the same compound ()

Question 17

formal charge

Answer 17

an electron bookkeeping system that allows us to discriminate between alternative Lewis structures; the different between the number of valence electrons and the number of electrons in the structure

Question 18

better Lewis structures have

Answer 18

fewer formal charges, smaller formal charges, and the negative formal charge on the more EN atom

Question 19

formal charge rules

Answer 19

1. sum in neutral atom must be zero
2. sum in an ion must equal the charge of the ion
3. small (or zero) formal charges on individual atoms are better than large ones
4. when formal charge cannot be avoided, negative formal charge should reside on the most EN atom