Chapter 6 - Chemical Bonding

Question 1

Why do atoms form chemical bonds?

Answer 1

They want to decrease their potential energy

Question 2

What is an ionic bond?

Answer 2

Chemical bonding that results from the electrical attraction between cations and anions

Electrons transferred

Question 3

What is covalent bond and what are the two types?

Answer 3

A bond that results from the sharing from two atoms

Polar-unequal attraction

Nonpolar-equal attraction

Question 4

What are the electronegativity difference cutoffs for the different bonds?

Answer 4

Nonpolar covalent (0.0-0.3) Polar covalent (0.4-1.7) Ionic (1.8-3.3)

Question 5

What is a chemical bond?

Answer 5

Mutual chemical attraction between the nuclei and valence electrons of different atoms that binds the atoms together

Question 6

What is a molecule?

Answer 6

A neutral group of atoms that are held together by covalent bonds

Question 7

What is a molecular compound?

Answer 7

A chemical compound whose simplest units are molecules

Ex:
H2O
O2

Question 8

What is a chemical formula?

Answer 8

It indicates the relative numbers of atoms of each kind in a chemical compound by using atomic symbols and numerical subscripts

Gives composition of a compound

Both ionic and covalent

Question 9

What is a molecular formula?

Answer 9

The type and numbers of atoms combined in a single molecule of a molecular compound

Question 10

How does potential energy change as atoms get closer and farther?

Answer 10

Very close and very far- high

Decrease as it approaches a distance where forces are =

Question 11

What is bond length?

Answer 11

The distance of two atoms at their minimum potential energy

Question 12

What is bond energy?

Answer 12

The energy required to break a chemical bond and form neutral isolated atoms

Question 13

What is the octet rule?

Answer 13

Chemical compounds tend to form so that each atom, by gaining, losing, or sharing electrons, has an octet of eight electrons in its highest energy level

Question 14

What are the three exceptions to the octet rule?

Answer 14

Hydrogen only wants two
Boron only wants 6 (it had 3 valence)
Main-group elements in period three and up can form bonds with expanded valence (more than 8 electrons) like sulfur

Question 15

What is electron dot notation?

Answer 15

An electron-configuration in which only the valence electrons are shown (as dots)

Question 16

What are Lewis structures?

Answer 16

Formulas in which atomic symbols represent nuclei and inner-shell electrons, dot-pairs or dashes represent electron pairs in covalent bonds and dots adjacent to only one atomic symbol represent unshared electrons

Question 17

What is a lone pair?

Answer 17

An unshared pair of electrons

Question 18

What is a structural formula?

Answer 18

It indicates the kind, number, and arrangement of bonds, but not the unshared pairs pf electrons

Question 19

What is a single/double/triple bond made of?

Answer 19

One/two/three pairs of electrons

Question 20

What are the four steps to making a Lewis structure?

Answer 20

Write each element, write valence electrons, write electron-dot for each, Carbon is always central (or least electronegative) but never Hydogen, add unshared pairs until each has eight

Question 21

For what three elements is a double bond common?

Answer 21

Carbon, nitrogen, oxygen

Question 22

What is resonance?

Answer 22

It refers to the bonding in molecules or ions that cannot be correctly represented by a single Lewis structure

Question 23

What are resonance structures or resonance hybrids and what goes between them?

Answer 23

The multiple valid Lewis structures for a given molecule or atom, double headed arrow

Question 24

What is formal charge (and formula)?

Answer 24

The difference between the number of valance electrons on the free atom and the number of valence electrons assigned to the atom in the molecule

(# of valence) - (number of bonds) - (number of unshared/non-bonded)