describe the structure of a typical atom
You can ignore the last paragraph of jamaica10’s answer because (1) chemists essentially never need to model atoms any better than with a nucleon - electron model and (2) jamaica10’s last paragraph is factually wrong. The rest is correct, but I’ll go ahead and give my own explanation.
All you need to know is the following:
At the center of an atom is the nucleus. The nucleus is made up of positively-charged protons and neutral neutrons bound together by a fundamental force called the strong force (presumably named such because it’s strong enough to overcome the electrostatic repulsion of all those positively charged protons). Collectively, protons and neutrons are sometimes called nucleons.
Swirling randomly in a gigantic (relative to the size of the nucleus) region around the nucleus called the electron cloud are the negatively charged electrons.
Electrons and protons have the same amount of charge – but of opposite type. Because the universe prefers stability, atoms generally have the same number of protons as electrons and hence are electrically neutral (macroscopically speaking – of course the exact positioning of the electrons and protons at a given instance may create a slight imbalance, but it’s a constantly self-rectifying electrical imbalance). That said, sometimes you can rip off an electron or two with really strong electromagnetic fields – the object (which now has a nonzero net charge) you’re left with is called an ion.
In terms of size, protons and neutrons are about the same, but electrons are about 1/2000th as big.
Later on you might learn about the different “electron shells” but this should work as a good first explanation of atomic structure.