Chapter 8

Question 1

Covalent bond

Answer 1

atoms share electrons

Question 2

Molecule

Answer 2

neutral group of atoms joined by covalent bonds

Question 3

Diatomic molecule

Answer 3

consisting of two atoms (e.g. oxygen molecule)

Question 4

Molecular compound

Answer 4

a compound composed of molecules

Question 5

Molecular compound melting point

Answer 5

relatively lower than those of ionic compounds

Question 6

Molecular formula

Answer 6

chemical formula of a molecular compound, shows how many atoms of each element a molecule contains

Question 7

Octet rule

Answer 7

atoms share to attain the electron configuration of noble gases

Question 8

Single covalent bond

Answer 8

two atoms held by sharing a pair of electrons, shown by a bar

Question 9

Double and triple covalent bonds

Answer 9

formed if the atoms can achieve the electron structure of noble gases

Question 10

Coordinate covalent bond

Answer 10

a covalent bond in which one atom contributes both bonding electrons

Question 11

Polyatomic ion

Answer 11

a tightly bound group of atoms that has a charge and behaves as a unit

Question 12

Bond dissociation energies

Answer 12

the energy needed to break the bond between two covalently bonded atoms, large energy corresponds to a strong bond

Question 13

A resonance structure

Answer 13

a structure that occurs when it’s possible to draw two or more valid electron dot structures that have the same number of electron pairs for a molecule or ion

Question 14

Exceptions to the octet rule

Answer 14

cannot be satisfied in molecules whose total # of valence electron is an odd #

Question 15

Molecular orbitals

Answer 15

when two atoms combine, this model assumes that their orbitals overlap to produce molecular orbitals

Question 16

Molecular orbitals belong to

Answer 16

a molecule as a whole

Question 17

Bonding orbital

Answer 17

a molecular orbital that can be occupied by two electrons of a covalent bond

Question 18

Sigma

Answer 18

symmetrical molecular orbital

Question 19

Pi

Answer 19

sausage-shaped molecular orbital, asymmetrical

Question 20

VSEPR theory

Answer 20

the repulsion between electron pairs causes molecular shapes to adjust so that the valence electron pairs stay as far apart as possible

Question 21

Orbital hybridization

Answer 21

provides information about both molecular bonding and molecular shape

Question 22

What happens in hybridization?

Answer 22

several atomic orbitals mix to form the total # of equivalent hybrid orbitals

Question 23

Non polar covalent bonds

Answer 23

when the atoms pull equally in the bond

Question 24

Polar covalent bond

Answer 24

when the atoms pull unequally in the bond

Question 25

The more electronegative atom

Answer 25

attracts electrons more strongly and gains a slightly negative chard

Question 26

The less electronegative atom

Answer 26

has a slightly positive charge

Question 27

Polar molecules

Answer 27

one end is slightly negative, the other end is slightly positive

Question 28

Dipole

Answer 28

a molecule that has two poles

Question 29

When polar molecules are placed between oppositely charged plates, what happens?

Answer 29

they tend to become oriented to the respective positive and negatively charged plates

Question 30

Intermolecular attractions

Answer 30

weaker than with ionic or covalent bonds

Question 31

Van der Waals forces

Answer 31

the two weakest attractions between molecules

Question 32

Dipole interactions

Answer 32

when polar molecules are attracted to one another

Question 33

Dispersion forces

Answer 33

weakest of all, caused by the motions of electrons

Question 34

Hydrogen bonds

Answer 34

a hydrogen covalently bonded to a very electronegative atom is weakly bonded to an unshared electron pair of another electronegative atom

Question 35

Network solids

Answer 35

solids in which all of the atoms are covalently bonded to each other

Question 36

Melting a network solid

Answer 36

requires breaking covalent bonds throughout a solid

Question 37

An example of a network solid

Answer 37

diamond

Question 38

Widely varying intermolecular attractions cause

Answer 38

a great range of physical properties among covalent compounds