Lesson 2 — Activity 3: Chemical Names and Formulas



Explore


As new elements were discovered, scientists around the world realized that they had a problem. They could not understand each other’s symbols and names for the elements. In 1919, however, a group of chemistry organizations from around the world came together and formed the International Union of Pure and Applied Chemistry (IUPAC).


 

These chemists established an international standard for chemical symbols and names. These standards were based on the names and symbols suggested by a Swedish chemist in 1817.

In this activity, you will learn more about chemical names, symbols, and formulas.



Names and Symbols

From your work with the periodic table, you will have noticed that element symbols are either one or two letters. Often the first letter of the element name is used.

For example, O for oxygen and S for sulfur.


When scientists ran out of letters, they began using the first letter of the element name and a second letter from the name.

For example, Co for cobalt and Mg for magnesium.



Some of the elements are a little more difficult to understand. They were discovered in ancient times and have Greek or Latin names. These elements were given a symbol based on their historic name.

For example, Hg for mercury from the Greek word hydrargyros meaning "water" and "silver."



Formulas


We use short forms and symbols to make it easier to communicate. You have already learned about some of the short forms used to represent the elements. In chemistry, we use a different element symbol to represent each element and a chemical formula to represent the compounds these elements form.

Chemical formulas are made up of letters and numbers.


1. Letters tell you which elements are in a substance.


2. Subscript numbers are written below and to the right and tell you how many atoms are in this element.


3. A subscript letter (also written below and to the right) tells you the state of matter, for example, solid, liquid, or gas.



Here's an example:

The chemical formula for water tells you that this substance is made up of the elements hydrogen and oxygen. It also tells you that there are two hydrogen atoms for every oxygen atom in the substance.


As well, the subscript letter that follows tells you if the substance is a solid, liquid, or gas at room temperature.

 

Digging Deeper

Click here  to go to the Study Jams! website to watch a video that reviews elements, compounds, and chemical formulas.

When you have finished watching the video, click on the "close" button in the upper right-hand corner to exit the video. Then, you can click on the "Test Yourself" button to see how much you know about elements, compounds, and chemical formulas.




Self-Check

Try This!


Try the questions below on your own first and then click on the tab to check your answers!

Complete the table below with the number and name of the elements and the number of atoms.
The first one has been completed for you as an example.

Name of Compound

Chemical
Formula

Name of
Elements

Total Number
of Atoms
 

carbon dioxide

CO2(g)

  

carbon and oxygen


  

   3


calcium carbonate

CaCO3(s)



    

magnesium chloride

MgCl2(s)