Elements: the simplest substances
Some things break down. Some never do.
Breaking things down
Metals like iron and non-metals like sulfur and oxygen are special. They are the simplest kinds of substances. But what makes a substance "simple"?
Chemists can break some substances into two or more simpler substances. Which of these do you think can be broken down into simpler substances?
What this lesson covers
The idea
An element is a substance that cannot be broken down into simpler substances; metals and non-metals are sub-categories of elements, 118 elements are known, and they are the basic building blocks of all matter.
Breaking things down
Metals like iron and non-metals like sulfur and oxygen are special. They are the simplest kinds of substances. But what makes a substance "simple"?
Chemists can break some substances into two or more simpler substances. Which of these do you think can be broken down into simpler substances?
- Water
- Iron
- Every substance can be
Can it be broken down?
Pick a substance, then press the button to try to break it down into simpler substances. Try all six. (Chemists do this with special methods in laboratories.)
Elements
An element is a substance that cannot be broken down into simpler substances.
Metals and non-metals are sub-categories of elements. At present 118 elements are known. They are the basic building blocks of all matter. Some occur naturally, while others are made artificially in the laboratory and do not exist in nature.
- Substance | Can it be broken down? | Element?
- Water | yes: hydrogen and oxygen | no
- Common salt | yes: sodium and chlorine | no
- Iron, sulfur, oxygen, carbon | no | yes
Notes
An element cannot be broken down into simpler substances. Metals and non-metals are kinds of elements. 118 elements are known: the basic building blocks of all matter.
Check yourself
An element is a substance that...
Which of these is an element?
Metals and non-metals are both kinds of...
How many elements are known at present?
Answer: 118 elements
118 elements are known. They are the basic building blocks of all matter.
- cannot be broken down into simpler substances — correct. Yes!
- can always be broken into two simpler substances. That describes substances like water. An element cannot be broken down.
- is always a solid. Oxygen is an element and it is a gas. State does not decide it.
- Water. Water breaks into hydrogen and oxygen, so it is not an element.
- Common salt. Salt breaks into sodium and chlorine, so it is not an element.
- Iron — correct. Yes! Iron cannot be broken down into simpler substances.
- elements — correct. Yes! Both are sub-categories of elements.
- alloys. Alloys are mixtures. Metals and non-metals are elements.
- plastics. Plastic is not an element at all.