Chemistry Ch 7 & 8

Front 1

Describe two ways an ion forms from an atom.

Back 1

-The loss of electrons to form a cation.
-The gain of electrons to form an anion.

Front 2

Define valence electrons.

Back 2

The electrons in the highest occupied energy level of an element's atoms.

Front 3

Why do nonmetals tend to form anions when they react to form compounds?

Back 3

Atoms of some nonmetallic elements tend to gain electrons to achieve a complete octet.

Front 4

Explain why ionic compounds are electrically neutral.

Back 4

The total positive charge of the cations equals in total negative charge of the anions.

Front 5

Explain why metals are good conductors of electricity.

Back 5

Electrons can flow freely through them.

Front 6

Describe the electrical charge of an ionic compound.

Back 6

They are neutral.

Front 7

What properties characterize ionic compounds?

Back 7

Ionic compounds can conduct an electric current when melted or dissolved in water.

Front 8

Define an ionic bond.

Back 8

The electrostatic forces that Hold ions together in ionic compounds.

Front 9

How can you represent the composition of an ionic compound?

Back 9

With chemical formulas.

Front 10

Why do ionic compounds conduct electricity when they are melted or dissolved in water?

Back 10

Wayne ionic compounds are melted or dissolved in water electrons can move freely through them.

Front 11

How do chemists model the valence electrons in metal atoms.

Back 11

The valence electrons of metal atoms can be model as a sea of electrons.

Front 12

How can you describe the arrangement of atoms in metals?

Back 12

Metal atoms are arranged in very compact and orderly patterns.

Front 13

Why are alloys more useful than pure metals?

Back 13

Alloys are more important because their properties are often superior to those of their component elements.

Front 14

Describe what is meant by ductile and malleable.

Back 14

Both the ductility and malleability of metals can be explained in terms of the mobility of valence electrons.

Front 15

Why is it possible to bend metals but not ionic crystals?

Back 15

Electrons flow freely in metals but not in ionic crystals.

Front 16

How are the melting points and boiling points of molecular compounds usually different from ionic compounds?

Back 16

Molecular compounds tend to have relatively lower melting and boiling points than ionic compounds.

Front 17

What information does a molecular formula provide?

Back 17

A molecular formula shows how many atoms of each element a molecule contains.

Front 18

What are the only elements that exist in nature as uncombined atoms? What term is used to describe these elements?

Back 18

Water and carbon monoxide ; diatomic molecule

Front 19

What electron configurations do atoms usually achieve by sharing electrons to form covalent bonds?

Back 19

In forming covalent bonds electron sharing usually occurs so that atoms of the chain the electron configurations of noble gases.

Front 20

How is an electron dot structure used to represent a covalent bond?

Back 20

An electron dot structure such as H: H represents the shared pair of electrons of the covalent bond by two dots.

Front 21

When are two atoms likely to form a double bond between them? A triple bond?

Back 21

Atoms form double or triple covalent bonds if they can attain a noble-gas structure by sharing the two pairs or three pairs of electrons.

Front 22

How is a coordinate covalent bond different from other covalent bonds?

Back 22

In a coordinate covalent bond the shared electron pair comes from one of the bonding atoms.

Front 23

How is the strength of a covalent bond related to its bond dissociation energy?

Back 23

A large bond dissociation energy corresponds to a strong covalent bond.

Front 24

List three ways in which the octet rule can sometimes fail to be obeyed.

Back 24

The octet rule cannot be satisfied in molecules whose total number of valence electrons is an odd number. There are also molecules in which atoms have fewer or more than a complete set of valence electrons.

Front 25

What kinds of information does a structural formula reveal about the compound it represents?

Back 25

The structural formula represents a covalent bonds by dashes and shows the arrangement of covalently bonded atoms.

Front 26

What are responsible for the properties of atom?

Back 26

Valence Electrons

Front 27

Atoms in the same column ...

Back 27

1. Have the same outer electron configurations.
2. Have the same valence electrons.

Front 28

State the octet rule.

Back 28

In forming compounds, atoms tend to achieve a noble gas configuration ; 8 in the outer shell is stable.

Front 29

What creates bonds between anions and cations?

Back 29

Opposite charges.

Front 30

What is the formula unit?

Back 30

The simplest ratio of elements in an ionic compound.

Front 31

What is a bond dissociation energy?

Back 31

The total energy required to break the bond between two covalently bonded atoms.