Untitled Lesson

Reading a Chemical Formula

Chemical Symbol

Subscript

Coefficient

Capital letter
followed by a

lowercase letter.
Tells you which
elements are in a
chemical formula

Small number that

comes after a chemical

symbol.

Tells you how many

atoms of each element

are in a chemical formula

Large number that comes
before a chemical symbol.

Tells you how many
molecules of each

element are in a chemical

formula

Reading a Chemical Formula

Chemical Symbol

Subscript

Coefficient
Na O

Reading a Chemical Formula

Chemical Symbol

Subscript

Coefficient

2 molecules of

Na O

2 atoms

of Na

1 atom

of O

sodium oxygen

Reading a Chemical Formula

Chemical Symbol

Subscript

Coefficient

sodium oxygen

2 atoms of Na

1 atom of O

C = 1
O = 2

CO

Elements

C
O

Subscript

2 capital letters

2 elements

Carbon and Oxygen

1 atom of C
2 atoms of O

Coefficient

There is no

coefficient so
there is only 1
molecule of CO

CO

1 molecule of CO

C = 1
O = 2

5CO

Elements

C
O

Subscript

2 capital letters

2 elements

Carbon and Oxygen

1 atom of C
2 atoms of O

Coefficient

There are 5
molecules

of CO

5

C = 1
O = 2

5CO
Number of

atoms of each

element

C = 1 x 5 = 5
O = 2 x 5 = 10

Subscript

1 atom of C
2 atoms of O

Coefficient

There are 5
molecules

of CO

5

There are 15 atoms

total in this

chemical formula.

5 molecules of CO

5CO

H = 3
P = 1
O = 4

Chemical Formula: H PO

# of Elements

# of Atoms of
each Element

H = 3
P = 1
O = 4

# of

Molecules

1

# of Atoms

total

H = 3
P = 1
O = 4

Chemical Formula: H PO

# of Elements
# of Atoms of
each Element

H = 3
P = 1
O = 4

# of

Molecules

1

# of Atoms

total

# of capital

letters

read the

subscript #

read the

coefficent #

add the # of

atoms together

H =
P =
O =

Chemical Formula: 3H PO

# of Elements
# of Atoms of
each Element
H =
P =
O =

# of

Molecules

# of Atoms

total

# of capital

letters

read the

subscript #

read the

coefficent #

add the # of

atoms together

Chemical
Formula

Number

of

elements

Name of
elements

Number of
atoms for

each

element

Number of
molecules

C =
H =
O =

2MgSO

HCu PO

1

3

3