Ch 6 Section 2

Question 1

A molecule is a neutral group of

Answer 1

Atoms that are held together by covalent bonds

Question 2

A single molecule of a chemical compound is an individual unit capable of

Answer 2

Existing on its own

Question 3

Molecules may consist of two or more

Answer 3

Atoms of the same element or two or more different atoms

Question 4

Molecular compound is a chemical compound whose

Answer 4

Simplest units are molecules

Question 5

The composition of a compound is given by

Answer 5

It’s chemical formula

Question 6

A chemical formula indicated the relative numbers of

Answer 6

Atoms of each kind in a chemical compound by using atomic symbols and numerical subscripts

Question 7

The chemical compound of a molecular compound is referred to as a

Answer 7

Molecular formula

Question 8

A molecular formula shows the types and numbers of

Answer 8

Atoms of each kind in a chemical compound by using atomic symbols and numerical subscripts

Question 9

The molecular formula for water reflects the fact that a single water molecule consists of

Answer 9

One oxygen atom joined by separate covalent bonds to two hydrogen atoms

Question 10

A molecule of oxygen O2 is an example of

Answer 10

A diatomic molecule

Question 11

A diatomic molecule is a molecule containing

Answer 11

Only 2 atoms

Question 12

The approaching nuclei and electrons are

Answer 12

Attracted to each other

Question 13

The attraction between nuclei and electrons corresponds to a decrease in

Answer 13

The total potential energy of the atoms

Question 14

The two nuclei repel each other and the two electrons

Answer 14

Repel each other which results in an increase in Potential energy

Question 15

Relative strength of attraction and repulsion between the charged particles depends on the

Answer 15

Distance separating the atoms

Question 16

When the atoms first sense each other the electron proton attraction is stronger than the

Answer 16

Electron electron and proton proton repulsions

Question 17

The atoms are drawn to each other and their

Answer 17

Potential energy is lowered

Question 18

The attractive force continues to dominate and the total potential energy continues to

Answer 18

Decrease until a distance is reached at which the repulsion between the like charges equals the attraction of the opposite charges

Question 19

When a distance is reached at which the repulsion between like charges equals the attraction of the opposite charges the potential energy is at a

Answer 19

Minimum and a stable hydrogen molecule forms (in the case of a hydrogen-hydrogen bond)

Question 20

A closer approach of the atoms results in a sharp rise in potential energy as

Answer 20

Repulsion becomes increasingly greater than attraction

Question 21

The bottom of the valley in the curve represents the

Answer 21

Balance between attraction and repulsion in a stable covalent bond

Question 22

The molecules electrons can be pictured as

Answer 22

Occupying overlapping orbitals moving about freely in either orbital

Question 23

The bonded atoms vibrate a bit but as long as their potential energy remains close to the minimum they are

Answer 23

Covalently bonded to each other

Question 24

The distance between two bonded atoms at their minimum potential energy is the

Answer 24

Bond length

Question 25

In forming a covalent bond the hydrogen atoms release energy as they

Answer 25

Change from isolated individual atoms to parts of a molecule

Question 26

The amount of energy released equals the difference between the

Answer 26

Potential energy at the zero level (separated atoms) and that at the bottom valley (bonded atoms)

Question 27

The same amount of energy must be added to separate the

Answer 27

Bonded atoms

Question 28

Bond energy is the energy required to

Answer 28

Break a chemical bond and form neutral isolated atoms

Question 29

Scientists usually report bond energies in kilojoules per mole (kJ/mol) which indicates the

Answer 29

Energy required to break one mile of bonds in isolated molecules

Question 30

Bond lengths and bond energies vary with the types of

Answer 30

Atoms that have combined

Question 31

Even the energy of a bond between the same two types of atoms

Answer 31

Varies somewhat depending on what other bonds the atoms have formed

Question 32

All individual hydrogen atoms contain a single unpaired electron in a

Answer 32

1s atomic orbital

Question 33

When two hydrogen atoms form a molecule they share

Answer 33

Electrons in a covalent bond

Question 34

Sharing electrons for hydrogen atoms allows each atom to have

Answer 34

The stable electron configuration of helium

Question 35

The tendency for atoms to achieve noble gas configurations my bonding covalently extends beyond the

Answer 35

Simple case of a hydrogen molecule

Question 36

Unlike other atoms the noble gas atoms exist

Answer 36

Independently in nature

Question 37

Noble gas atoms possess a minimum of energy existing on their own because of the

Answer 37

Special stability of their electron configurations

Question 38

Other main group atoms can effectively fill their outermost s and p orbitals with electrons by

Answer 38

Sharing electrons through covalent bonding

Question 39

Such bond formation follows the

Answer 39

Octet rule

Question 40

Octet rule: chemical compounds tend to form so that each atom by gaining losing or sharing electrons has an

Answer 40

Octet of electrons in its highest occupied energy level

Question 41

Most main group elements tend to form covalent bonds according to the

Answer 41

Octet rule

Question 42

Because electron pairs are shared in covalent bonds boron tends to form bonds in which

Answer 42

It is surrounded by six electrons

Question 43

Other elements can be surrounded by more than with electrons when they

Answer 43

Combine with the highly electronegative elements fluorine, oxygen, and chlorine

Question 44

In these cases of expanded valence bonding involves electrons in

Answer 44

D orbitals as well as in s and p orbitals

Question 45

Covalent bond formation usually involves only the electrons in an atoms

Answer 45

Outermost energy levels, the atoms valence electrons

Question 46

Electron for notation is an electron configuration notation in which

Answer 46

Only the valence electrons of an atom of a particular element are shown indicates by dots places around the elements symbol

Question 47

In electron dot notation the inner shell electrons

Answer 47

Are not shown

Question 48

In general an elements number of valence electrons can be determined by adding the

Answer 48

Superscripted of the elements noble gas notation

Question 49

The pair of dots between the two symbols represents the

Answer 49

Shared pair of a covalent bond

Question 50

An unpaired pair (lone pair) is a pair of electrons that is not

Answer 50

Involved in bonding and that belongs exclusively to one atom

Question 51

The pair of dots representing a shared pair of electrons in a covalent bond is often replaced by a

Answer 51

Long dash

Question 52

Lewis structures: formulas in which atomic symbols represent

Answer 52

Nuclei and inner shell electrons, for pairs or dashes between two atomic symbols represent electron pairs in covalent bonds, and dots adjacent to only one atomic symbols represent unshared electrons

Question 53

It is common to write Lewis structures that show only the

Answer 53

Electrons that are shared, using dashes to represent the bonds

Question 54

A structural formula indicated the

Answer 54

Kind number arrangement and bonds but not the unshared pairs of the atoms in a molecule

Question 55

The Lewis structures for many molecules can be drawn if one knows the

Answer 55

Composition of the molecule and which atoms are bonded to each other

Question 56

A single covalent bond (single bond) is a covalent bond in which

Answer 56

One pair of electrons is shared between 2 atoms

Question 57

Atoms of some elements can share

Answer 57

More than one electron pair

Question 58

A double covalent.bond (double bond) is a covalent bond in which

Answer 58

2 pairs of electrons are shared between 2 atoms

Question 59

A double bind is shown either by two

Answer 59

Side by side pairs of dots or by two parallel dashes

Question 60

All four electrons in a double bond belong to

Answer 60

Both atoms

Question 61

A triple bond is a covalent bond in which

Answer 61

3 pairs of electrons are shared between two atoms

Question 62

Multiple bonds

Answer 62

Double and triple bonds

Question 63

Double bonds in general have greater

Answer 63

Bond energies and are shorter than single bonds

Question 64

Triple bonds are even

Answer 64

Stronger and shorter

Question 65

In writing Lewis structures for molecules that contain carbon nitrogen or oxygen one must remember that

Answer 65

Multiple bonds between pairs of these atoms are possible

Question 66

A hydrogen atom always forms a

Answer 66

Single covalent bond

Question 67

The need for a multiple bond becomes obvious if there are not enough

Answer 67

Valence electrons to complete octets by adding unshared electrons

Question 68

Some molecules and ions cannot be represented

Answer 68

Adequately by a single Lewis structure

Question 69

Resonance refers to bonding in

Answer 69

Molecules or ions that cannot be correctly represented by a single Lewis structure

Question 70

To indicate resonance a double headed arrow is

Answer 70

Placed between a molecules resonance structures

Question 71

There are many covalently bonded compounds that do not contain individual molecules but instead can be pictures as

Answer 71

Continuous 3 dimensional networks of bonded atoms

Question 72

Many chemical compounds including most of the chemicals that are in living things and are produced by living things are composed of

Answer 72

Molecules