Chemical Formulas
Chemical Formula:
An easy way for scientist to describe a
molecule using the element symbols.
H 2O
C02
REMEMBER…
When you read a chemical formula,
each new element begins with a
capital letter. So if you see CO2, you
should think Carbon and Oxygen.
However…
If you see a lower case letter in a
chemical formula, it goes with the
capital letter that comes before it.
For example:
If you see NaCl, you should think
(Na)Sodium and (Cl)Chlorine.
Reading Chemical Formulas
NaCl
Sodium
Chlorine
Reading Chemical Formulas
This subscript tells us
there
are 2 atoms of hydrogen in
this formula.
H2O
Hydrogen
If no subscript is present,
it is understood the
subscript is 1. So there is 1
Atom of oxygen in this formula
Oxygen
Subscript – number that follows
a symbol; subscript tells how
many atoms of element are in
molecule
Reading Chemical Formulas
The
coefficient
shows us
there are 2
molecules of
water in this
formula.
2H2O
Hydrogen
Coefficient:
The coefficient
in this formula
tells us there
are 4 hydrogen
atoms and 2
oxygen atoms
Oxygen
The large number before an
element symbol or compound that represents the
number of elements or compounds. You multiply
the coefficient by the subscript to find the number
of atoms of each element.
Reading Chemical Formulas
2CO2
Carbon
Oxygen
What elements are bonded to create
this molecule of Carbon Dioxide?
How many atoms of each element are in
this molecule of Carbon Dioxide?