Chapter 19 Review

TEST TOMORROW

Water molecules are _____ because one end is partially positive and one end is partially negative.

a. polar

b. nonpolar

c. polyatomic

d. ionic

POLAR Covalent Bonds- UNEQUAL SHARING of electrons between

NONMETALS

+

-A water molecule is POLAR because it has a partially positive end and a partially negative end.

In a chemical formula, the _________ tells how many atoms of that element are in a unit of the compound.

a. superscript

b. oxidation number

c. subscript

d. chemical symbol

How many atoms of each element are in the compound potassium sulfate?

Submarine !

Potassium = 2

Sulfur = 1

Oxygen = 4

Subscript (written below)

K2SO4

A chemical bond that occurs when atoms share electrons is a(n) ________ bond.

a. covalent

b. ionic

c. magnetic

d. polyatomic

Covalent Bonds- SHARING of electrons between NONMETALS

+ -Partially positive charged end

Partially negative charged end

The shared electron will spend more time near the chlorine atom.

What type of bond will we form?

Chlorine is a nonmetals, iodine is a nonmetal!

The __________ tells you how many electrons an atom must gain, lose, or share to become stable.

a. atomic mass

b. atomic number

c. ionic number

d. oxidation number

Let’s Look…..

The oxidation number (charge) tells you how many electrons an atom has gained, lost, or shared to become stable. Written as superscripts (above symbol).

-2 Charge

+1 Charge

+1 Charge

The sum of the oxidation numbers in a neutral compound is ALWAYS _______.

a. a negative number

b. a positive number

c. one

d. zero

Na+1 + Cl-1 NaCl+1-1=0

The sum of the oxidation numbers are ALWAYS ZERO = Neutral

Oxidation Number

The oxidation number of an atom is shown with a _________.

a. negative number

b. positive number

c. subscript

d. superscript

Na+1 + Cl-1 NaCl

Oxidation Number = Superscript (written above)

Oxidation Number = superscript

Superman !

How many electrons are needed in the outer energy levels of most atoms for the atom to be chemically stable?

a. 2

b. 4

c. 6

d. 8

RULE !

1st energy level: 2 electrons

2nd energy level: 8 electrons

3rd energy level: 8 electrons

What kind of chemical bond is formed when a transfer of electrons occurs?

a. covalent

b. hydrated

c. ionic

d. magnetic

Ionic Bond – TRANSFER OF ELECTRONS!

METAL – Left of periodic table

NONMETAL – Right of periodic table

What is the total number of atoms in the compound Ca(ClO3)2.

a. 2

b. 3

c. 5

d. 9

Let’s Look…..

Ca(ClO3)2

calcium = 1

chlorine = 2

oxygen = 6

What is the name of the compound with the formula PO2.

a. Phosphorus oxide

b. Monophosphorus oxide

c. Monophosphorus dioxide

d. Phosphorus dioxide

Why do the noble gases NOT form compounds readily?

a. They have empty outer energy levels

b. They have no electrons

c. They have seven electrons in the outer energy levels

d. Their outer energy levels are completely filled with electrons

Which of the following is the correct formula for magnesium nitrate? (Mg+2 and NO3

-1)

a. MgNO3

b. Mg2NO3

c. Mg(NO3)2

d. Mg2(NO3)2

Mg+2 and NO3-1

Mg+2 and NO3-1

21

Mg(NO3)2

What is the oxidation number of phosphorus in K3P?

a. -7

b. -3

c. +1

d. +3

K P3 1

+1 -3

REVERSE THE CRISS-CROSS METHOD TO DETERMINE CHARGE!

What is the correct name for K2SO4.

a. Potassium disulfide

b. Potassium sulfate

c. Potassium sulfide oxide

d. Potassium (II) sulfate

What type of bond is formed in the figure below?

a. ionic

b. metallic

c. covalent

d. atomic

What type of bond is formed in the figure below?

a. ionic

b. metallic

c. covalent

d. atomic

An example of a nonpolar covalent molecule is ___________

a. H2O

b. LiBr

c. N2

d. Ca(OH)2

NONPOLAR Covalent Bond- EQUAL SHARING of electrons between

NONMETALS

Chlorine molecule

Chlorine atom

Chlorine atom

All of the compounds below are binary compounds EXCEPT

a. LiCl

b. MgF2

c. N2

d. Ca(OH)2

What is a binary compound?

• A binary compound is one that is

composed of 2 elements.

– 2 Types of Binary compounds:

• Binary ionic compound (metal + nonmetal) Ex. LiBr

• Binary covalent compound (nonmetal + nonmetal) Ex. N2

Which chemical formula below accurately represents the binary covalent compound N2O5?

a. Nitrogen pentoxygen

b. Nitrogen pentoxide

c. Dinitrogen oxide

d. Dinitrogen pentoxide

Binary Covalent Compound

• Covalent compounds are formed between nonmetals.

• Prefixes are used to indicate how many atoms of each element are in a binary covalent compound.

• Often the prefix mono- is omitted, although it is used in some cases (Ex. CO carbon monoxide)

Covalent Compound

Chemical Name

N2O dinitrogen oxide

NO nitrogen oxide

NO2 nitrogen dioxide

Which chemical formula below contains a polyatomic ion?

a. NO2

b. NO3

c. NaNO3

d. Na3N

What would be the oxidation number for calcium (Ca)?

a. +2

b. -2

c. +6

d. -6

Calcium is in group 2 = 2 valence electrons. It is EASIER for calcium to LOSE 2 electrons than to gain 6! Calcium loses two NEGATIVES +2

+2

What would be the oxidation number for sulfur (S)

a. -6

b. +6

c. -2

d. +2

Sulfur is in group 6 = 6 valence electrons. It is EASIER for calcium to GAIN 2 electrons than to

LOSE 6! Sulfur gains two NEGATIVES -2

-2

Good Luck!!!