Navigation
Discovering pure substances that cannot be broken down into simpler parts.
If you took a piece of pure silver and chopped it into smaller and smaller bits, would you ever reach a point where you couldn't chop it anymore without it changing into something else?
Imagine the entire universe is built out of LEGO bricks. An element is like a brick of a single color and shape. An element is a pure substance that is made of only one kind of atom. Because every atom in an element is the same, you cannot break an element down into anything simpler. If you have a pile of gold atoms, no matter how much you heat them or crush them, they will always be gold. Scientists have discovered about different elements that act as the 'ingredients' for everything on Earth!
Let's look at a 24-karat gold coin. 1. Look at the coin: It is made entirely of gold. 2. Zoom in: Every single tiny particle inside is a gold atom. 3. Conclusion: Because there is only type of atom present, the coin is a pure element.
Quick Check
If a substance is made of two different types of atoms joined together, is it still an element?
Answer
No, an element must be made of only one kind of atom.
Not everything we see is an element. In fact, most things are mixtures. A mixture is what you get when you put different elements together without them permanently sticking. Think of a bowl of trail mix. You have raisins, nuts, and chocolate. You can see the different parts and even pick them apart. An element is different; it is 'pure.' In an element like Oxygen (), every piece is identical. In a mixture like air, you have Oxygen mixed with other elements like Nitrogen () and Argon ().
Is a bucket of dry sand an element or a mixture? 1. Observe: Sand is made of tiny bits of shells, rocks, and minerals. 2. Analyze: These bits are made of many different types of atoms. 3. Result: Since it contains many different 'ingredients' that aren't all the same, sand is a mixture, not an element.
Quick Check
Why is a bowl of salt and pepper considered a mixture instead of an element?
Answer
Because it contains two different substances (salt and pepper) that can be seen and separated.
Elements aren't just in science labs; they are all around you! - Oxygen (): A colorless gas in the air that humans need to breathe to survive. - Gold (): A shiny, yellow metal found deep in the Earth's crust, often used for jewelry because it doesn't rust. - Carbon (): This element is found in the 'lead' of your pencil (graphite) and is also a main building block of all living things, including you!
Is a standard wooden pencil a pure element? 1. Identify the parts: A pencil has a wooden outer shell, a graphite core, and a rubber eraser. 2. Evaluate the core: The 'lead' is actually graphite, which is the element Carbon. 3. Evaluate the whole object: Because the whole pencil is made of wood, rubber, and carbon, the pencil itself is a complex mixture of many elements!
What is the smallest 'piece' of an element called?
Which of these is a pure element found in nature?
True or False: You can use heat to turn the element Gold into a simpler substance.
Review Tomorrow
Tomorrow morning, try to name three elements you might have interacted with today (Hint: think about your pencil, the air, or jewelry).
Practice Activity
Go on an 'Element Hunt' in your kitchen. Look for aluminum foil or a copper penny. Are these pure elements or mixtures?