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Take a look inside an atom to see the even smaller parts that live there.
Imagine you have a piece of gold and you keep cutting it in half until it is so small you can't see it anymore. What is the very last, tiny 'Lego brick' that makes up that gold? It's called an atom, and it has a whole world hidden inside it!
At the very center of every atom is a tiny, heavy core called the nucleus. You can think of the nucleus like the 'brain' or the 'sun' of the atom. It is very small compared to the rest of the atom, but it holds almost all of the atom's weight. Inside this nucleus, there are two types of particles packed tightly together: protons and neutrons.
Protons are special because they have a positive charge, which we write as . Neutrons are about the same size as protons, but they are 'neutral,' meaning they have no charge at all (). Together, they stay glued in the center to form the foundation of everything in the universe!
Quick Check
Which two particles are found inside the nucleus at the center of the atom?
Answer
Protons and Neutrons.
While the protons and neutrons are hanging out in the nucleus, the electrons are the 'busy bees' of the atom. Electrons are much, much smaller than protons. In fact, it would take about electrons to weigh as much as just one proton!
Electrons have a negative charge, written as . Instead of sitting still, they zoom around the nucleus at incredible speeds. They don't fly off into space because their negative charge is attracted to the positive charge of the protons, just like magnets! They move so fast that they create a 'cloud' around the nucleus.
To understand how much space is in an atom, imagine a giant football stadium: 1. The nucleus (protons and neutrons) would be like a small marble sitting right on the 50-yard line. 2. The electrons would be like tiny gnats buzzing all the way up in the very highest seats of the stadium. 3. Everything in between the marble and the gnats is just empty space!
Quick Check
True or False: Electrons are larger than protons.
Answer
False. Electrons are much smaller than protons.
Most atoms like to be 'balanced.' This means they want to have the same number of positive and negative charges. If an atom has positive protons, it will usually have negative electrons.
Because the from the protons and the from the electrons cancel each other out, the whole atom becomes neutral. The neutrons are also there in the nucleus, acting like 'spacers' or 'glue' to help the protons get along, but they don't change the charge because they are .
Let's look at a Helium atom (the gas used in balloons): 1. Place protons in the center nucleus (Total charge: ). 2. Add neutrons to the nucleus to keep it stable. 3. Add electrons zooming around the outside (Total charge: ). 4. The total charge is . The atom is balanced!
Imagine you find an atom with protons in the nucleus. 1. Where would you look to find the electrons? (Answer: Moving in the space outside the nucleus). 2. If the atom is balanced, how many electrons should be zooming around? (Answer: electrons). 3. If you added more neutron to the nucleus, would the atom's charge change? (Answer: No, because neutrons have charge).
What is the name of the center part of the atom?
Which particle has a positive () charge?
Electrons sit perfectly still inside the nucleus.
Review Tomorrow
Tomorrow morning, try to name the three parts of the atom and remember which one 'zooms' around the outside.
Practice Activity
Grab some different colored candies or cereal. Use one color for protons, one for neutrons, and one for electrons to build your own 'balanced' Lithium atom ( protons, neutrons, electrons) on a plate!