carbon
(C)
fluorine
(F)
lithium
(Li)
sodium
(Na)
oxygen
(O)
nitrogen
(N)
sulfur
(S)
hydrogen
(H)

People who deal with chemicals either at work or at school need a common way to describe these things.  All over the world, companies, schools, and others use a single method to describe what atoms are doing in reactions.

It was discovered that WATER has two hydrogen atoms and one oxygen atom.  How should people refer to this chemical?  Since there are two Hydrogen atoms and one Oxygen atom, the FORMULA  H2O is used.  The little "2" means that there are two atoms of Hydrogen present in the particle.  The "2" is called a "subscript".   Since the  "O" has no subscripted number,  it means that there is only one atom of Oxygen present.
 

  atoms present 
  formula 
  common name 
what a simple model 
might look like
2 Hydrogen & 
1 Oxygen
H2O
water

Why is any other formula incorrect?

ANSWER:  Any other combinations of atoms are not water!  For example, H2O2 is Hydrogen Peroxide, and H3O is something called "hydronium".

(+8)Use books or other sources to fill in the empty spaces in the tables.
 

  atoms present 
  formula 
  common name 
what a simple model 
might look like
   
carbon dioxide
 

 
  atoms present 
  formula 
  common name 
what a simple model 
might look like
   
ammonia
 

 
  atoms present 
  formula 
  common name 
what a simple model 
might look like
   
baking soda
 

 
  atoms present 
  formula 
  common name 
what a simple model 
might look like
   
battery acid

 

Sometimes, you will see an additional number with the formula, like this:   2H2O.  This means that there are two water particles present.  Why does this happen?  Often, chemical reactions take place and involve more than one particle of a particular type.  For example, the reaction that produces water at first glance look like this:

H2 + O2 ==> H2O

This is pretty accurate, but scientists have discovered that there are two H2 particles required for the reaction, and that two water particles are created instead of just one.  The real reaction looks like this:

2H2 + O2 ==> 2H2O

The big "2" in front of the H2 and the H2O are called COEFFICIENTS.  They tell you how many particles are present.  How would the quation above be drawn?
 
 
+   ===>

(+8)Fill in the tables with drawings...

3H2O

 

 

HCl

 

 

NH3

 

 

4Na