Lesson 9 — Activity 3: The Periodic Table of Elements
Completion requirements
Lesson 9 — Activity 3:
The Periodic Table of Elements
Explore
You have already worked a little bit with the periodic table of elements. In this activity, you will learn about where it came from and how it works.
A periodic table is a table in which the elements are organized by their physical and chemical properties.
The periodic table was developed by Dmitri Mendeleev, a Polish citizen, in 1869. He organized the elements that had been discovered up to that time into a chart that showed that the properties of the elements vary periodically as the atomic mass increases.
@gettyimages
A
property is a characteristic that describes a particular substance, such
as its colour, lustre (shininess), melting point, crystal shape,
solubility, or density. An atomic mass is the mass of 1 atom of an
element.
A property is a characteristic that describes a particular substance, such as its colour, lustre (shininess), melting point, crystal shape, solubility, or density. An atomic mass is the mass of 1 atom of an element.
Mendeleev had one problem: There were blank areas or gaps in his chart. He predicted that new elements that had not been discovered yet would fill the blanks. Many scientists did not agree with him, but within 16 years, enough new elements had been found to fill the blanks properly! The periodic table that you have been using is based on the design of the table Mendeleev designed.
The periodic table is arranged in a series of boxes in columns and rows.
- Each vertical column is a group, or family, of elements numbered from 1 to 18. These groups have similar chemical properties.
- Each horizontal row is called a period numbered from 1 to 7. You can use the period and group numbers to find a specific element. For example, find period 6 and go across to group 11. The element is Au (gold).
An atomic symbol has three parts to it:
1. the symbol: the usual element symbol
2. the atomic number: equal to the number of protons
3. the mass number: equal to the number of protons and neutrons in the isotope (atoms of elements with different numbers of neutrons)
Take a look at the example below that shows the different parts of the element Iron (Fe).
@gettyimages
1. the symbol: the usual element symbol
2. the atomic number: equal to the number of protons
3. the mass number: equal to the number of protons and neutrons in the isotope (atoms of elements with different numbers of neutrons)
Take a look at the example below that shows the different parts of the element Iron (Fe).
@gettyimages
Click here to to go a website with an interactive periodic table of the elements. Click on some of the elements to learn more about them!
Click on the Play button to watch a video that further explains the periodic table of elements as well as gives you more information about Dmitri Mendeleev.
Click on the Play button to watch a video that further explains the periodic table of elements as well as gives you more information about Dmitri Mendeleev.
Self-Check
Try This!