General Chemistry Chapter 3: Bonding and Chemical Interaction

Question 1

What does the octet rule state?

Answer 1

elements will be most stable with eight valence electrons

Question 2

What are exceptions to the octet rule?

Answer 2

• Elements with an incomplete octet are stable with fewer than eight electrons and include H, He, Li, Be and B
• Elements with an expanded octet are stable with more than eight electrons (period 3 or greater)
• Compounds with an odd number of electrons cannot have eight electrons on each element.

Question 3

What is an ionic bond?

Answer 3

formed via the transfer of 1 or more electrons from an element with a relatively low ionization energy to an element with a relatively high electron affinity.

Question 4

What types of elements generally form ionic bonds?

Answer 4

Generally forms between metals and nonmetals

Question 5

What is a positively charged ion called? Negatively?

Answer 5

\+ = cation
- = anion

Question 6

What doe ionic compound form? (structure)

Answer 6

Crystalline lattice - large organized arrays of ions

Question 7

What are special properties of ionic compounds?

Answer 7

tend to dissociate in water and other polar substances

tend to have high melting points

Question 8

What is a covalent bond?

Answer 8

sharing of electrons between elements of similar electronegativities

Question 9

What is a bond order?

Answer 9

Refers to whether a covalent bond is a single bond, double bond or triple bond. As bond order increases, bond strength increases, bond energy increases and bond length decreases.

Question 10

When are covalent bonds considered nonpolar?

Answer 10

when there is either no difference or a small difference in electronegativity between the atoms (

Question 11

When are covalent bonds considered polar?

Answer 11

when there is a significant difference in electronegativity (0.5 to 1.7), but not quite to the extent that would be seen in an ionic bond.

Question 12

What are coordinate covalent bonds?

Answer 12

a single atom provides both bonding electrons while the other atom does not contribute any; coordinate covalent bonds are most often found in Lewis acid-base chemistry .

Question 13

When do formal charges exist?

Answer 13

When an atom is surrounded by more or fewer valence electrons than it has in its neutral state.

Question 14

What are resonance structures?

Answer 14

differences in configurations/distribution of electrons

Question 15

What is the valence shell electron pair repulsion theory?

Answer 15

predicts the 3D molecular geometry of covalently bonded molecules. In this theory, electrons arrange themselves as far apart as they can.

Question 16

Which results in more repulsion? Bonding or non-bonding electrons?

Answer 16

Non-bonding

Question 17

What are sigma bonds?

Answer 17

the result of head-to-head overlap

Question 18

What are pi bonds?

Answer 18

the result of overlap of two parallel electron cloud densities.

Question 19

What are three types of intermolecular forces?

Answer 19

electrostatic attractions between molecules. They are significantly weaker than covalent bonds.

Question 20

What are london dispersion forces?

Answer 20

interaction in all atoms and molecules that increases as size increases

Question 21

What are dipole-dipole interactions?

Answer 21

occur between the oppositely charged ends of polar molecules, stronger than London, interactions are evident in the solid and liquid, negligible in gas

Question 22

What are hydrogen bonds?

Answer 22

special d-d interaction. Occurs when hydrogen is bound to fluorine, oxygen or nitrogen.