In this lesson we will discuss the setup and structure of the periodic table and some of the ways that the periodic table can be used. We will look at how the elements are ordered and what the row and column that an element is in tells us.
Periodic Table Structure
Think of your favorite food. What is it made of? Maybe you thought about pizza. Pizza is made from pizza crust, cheese, pizza sauce and your favorite toppings, right? Now think about the cheese, what is it made from? It is made from milk, but what is the milk made from? Everything you can think of is made from tiny things called atoms, which cannot be seen. Each of those atoms are either a single element from the periodic table or two or more elements from the periodic table, known as a compound. Let’s look at elements in more detail.
Elements: The Blocks of the Periodic Table
Elements are substances that cannot be broken into any other substance. An example of an element you may know is gold. No matter how small you cut or break a gold ring, all the pieces are still gold. There are over 100 elements that we know exist in our world. Each one has its own name, symbol and number.
Each element’s number is called its atomic number. The atomic number is used to order the elements in counting order from left to right across the periodic table. Each element’s block on the periodic table, like the block shown above, contains that element’s atomic number, symbol, name and atomic mass (the mass of each atom of that element). In the image above, the element carbon’s atomic number is 6, its symbol is C and its atomic mass is 12.0107.
Think of the blocks like house addresses for each element. The periodic table is divided into groups (up and down columns) and periods (left to right rows). The address for each element is given by the group number and the period number. Groups are numbered 1-18, and periods are number 1-7. Look at the periodic table below. The element that lives at group 13, row 2, for instance, is Boron (B). Its atomic number is 5.
Uses of the Periodic Table
The way the periodic table is put together tells us other information too. Scientists use the periodic table to see what group (address) an element is located in. Each member of the same group shares similar properties as the other members of the group.
Another use for the periodic table is to tell you if an element is a metal, nonmetal or metalloid (an element that has properties of both metals and nonmetals). On the periodic table, there is a line that looks like a set of stairs, called the staircase, that separates all the metals to the left of the line (shown in blue in the image above), except hydrogen, and the nonmetals to the right of the line (shown in yellow). The elements right along the staircase are the metalloids (shown in pink).
The periodic table is useful to find many pieces of information with a quick look, including an element’s address, atomic number, symbol, name and mass of an element’s atom. At a glance we can determine if an element is a metal, nonmetal or metalloid just by its position on the periodic table.