Chapter 8:

Question 1

What does the Lewis structure tell us?

Answer 1

How atoms are connected in a molecule

Question 2

Ionic Bond:

Answer 2

Electrostatic attraction between cation and anion, transfer of valence electrons (metal and nonmetal)

Question 3

Covalent bond:

Answer 3

Sharing of valence electrons between nonmetals (includes metalloids)

Question 4

Metalic bonds:

Answer 4

Dissociation of metals electrons causing a sea of shared electrons

Question 5

What are the guidelines for the Lewis structure?

Answer 5

1) Determine the total number of valence electrons
2) Arrange the element symbols and connect with single bonds
a. atom with greatest bonding capacity in center
b. With equal bonding capacities least electronegative atom in the center
3) Complete octets of non-central atoms by adding lone pair
4) Compare valence electron numbers and attach extra valence electrons to central atom
5) Complete central atom octet

Question 6

How is bonding capacity determined?

Answer 6

How many electrons the element needs to get an octet

Question 7

What is the trend for electronegativity?

Answer 7

Electronegativity or electron affinity, increases left to right and decreases top to bottom

Question 8

What determines the chemical activity of a molecule?

Answer 8

Connectivity- how the atoms connect in the specific molecule

Question 9

Resonance:

Answer 9

When two or more equivalent Lewis structures can be drawn for one compound

Question 10

Resonance:

Answer 10

When two or more equivalent Lewis structures can be drawn for one compound

Question 11

Resonance structures:

Answer 11

Two or more Lewis structures with the same arrangement of atoms but different arrangement of bonding pairs of electrons

Question 12

Octet Rule:

Answer 12

Atoms tend to lose, gain, or share electrons to obtain a set of eight valence electrons

Question 13

Bonding pair of electrons:

Answer 13

Pair of electrons shared between two atoms in a covalent bond

Question 14

Polar covalent bond:

Answer 14

Unequal sharing of bonding pair of electrons between two atoms resulting in uneven distribution of charge

Question 15

Bond polarity:

Answer 15

A measure of the extent to which bonding electrons are unequally shared due to differences in electronegativity of the bonded atoms

Question 16

Polar bond arrow:

Answer 16

Arrow points to more negative end of bond

Question 17

Electronegativity:

Answer 17

Relative ability of an atom to attract electrons in a bond to itself

Question 18

Allotropes:

Answer 18

Different molecular forms of the same element

Question 19

How is Formal Charge found? (What is the formula)

Answer 19

(FC) = (number of valence electrons) - [(number of unshared e-) + 1/2 (number of e- in bonding pairs)]

Question 20

Formal Charge:

Answer 20

Charge on atom with more or less valence electrons than it is supposed to have.

Question 21

What are the criteria of the most stable resonance structures?

Answer 21

Formal charges equal or are close to zero
negative formal charges on the more electronegative element

Question 22

Electron deficient:

Answer 22

Molecules with atoms having fewer than eight electrons

Question 23

Free radicals:

Answer 23

Molecules having an odd number of electrons

Question 24

Expanded valence shell:

Answer 24

Molecules with atoms having more than an octet

Question 25

When are expended valence shells seen?
And when does this occur?

Answer 25

Seen for elements with Z > 12
Occurs in molecules with strongly electronegative elements (F, O Cl) and when expanded shell decreases formal charge on the central atom

Question 26

Why do expended valence shells seen happen?

Answer 26

The electrons use empty d orbitals