Basic Atomic Structure: A Look Inside the Atom
let's take a closer
look
atatom
satom
s are the building blocks that make up everything all stuff everywhere here I've got some drawings this is table salt a solid here's water a liquid and finally oxygen gas and what we'relook
ing at here is what we'd see if we could take these three things and zoom in zillions and zillions and zillions of times and if we couldlook
at these closely enough we'd be able to see theatom
s these little building blocks that make everything upnow
atom
s aren't really little colored circles but it's a good way to think about them and it's the way we'll usually draw them when we're learning about this stuffatom
s are super tiny they are so tiny it can be really hard to wrap your head around how tiny they are here is something that might help you think about this take a piece of paperlook
at how wide it is here all right this is so incredibly thin nowatom
s are so small that it would take 1 millionatom
s lined upnext to each other in a row to be as thick as this tiny width of paper that's how small
atom
s are now what I want to do now islook
even closer at now let's take one of theseatom
s here and zoom in even more so we can see what's inside of it here's a magnified view of oneatom
it's not a perfect representation of exactly what anatom
wouldlook
like but it's close enough for right now and check this out theatom
itself is made up of even smaller things right so that wesaid abs are like the building block for all of stuff but then if you
look
at anatom
it has even smaller building blocks that make it up so in the center of theatom
is something called the nucleus and the nucleus is made up of two tiny particles there are protons which I've drawn as red circles here and then they're neutrons which I've drawn as blue circles nucleus is here in the middle of theatom
and then on the outside of theatom
there are these little black circles thatI'm using to to represent electrons the electrons you'll see are connected to these sort of oval paths and I've drawn these in to show that the electrons are constantly moving they're flying around the outside of the
atom
at an incredibly high speed whereas the nucleus stays solid here right in the middle of theatom
now electric charge is very important when we're talking aboutatom
s for a number of reasons protons have a positive charge a proton has a charge of 1 pluselectrons on the other hand have a negative charge one electron has a charge of 1 minus now neutrons they don't have an electric charge at all of charge of 0 and neutral is a word that we use to refer to something that doesn't have a charge so neutrons sounds a lot like neutral now positive and negative charges attract remember that opposite charges attract and that has important consequences for how this
atom
works we said that these electrons are flying around the outside of theatom
they're moving really fast so why don't they just fly out into space well the reason why is because the negatively charged electrons are attracted to the positively charged protons so the protons kind of pull the electrons in they keep them from just flying away but the electrons are moving around so fast that they're not able to actually pull in here and actually touch the protons so that's why they keep staying on the outside and don't just crash in here and all touch the
protons now sometimes people ask well neutrons neutrons don't have a charge why are they important at all well it seems that neutrons help keep all of the particles in the nucleus strongly connected to each other now electrical charge is important something else that's important with
atom
s is what their masses how much they weigh so in order to figure that out we have tolook
at the mass of the various things that make up theatom
now a proton and a neutron are very very similar in sizeand in mass and they both weigh about this many grams
mass unit and they said okay one proton or one Neutron weighs about 1
look
at what a tiny number this is right there's a decimal place all the way over here this is a number that it's best to represent in scientific notation instead but however you write this it's a really tiny unwieldy number so scientists came up with another way to to measure the mass of a proton or neutron and that's using a unit called the AMU theatom
ic
mass unit and they said okay one proton or one Neutron weighs about 1amu that's a lot easier to use than this measurement here so proton or neutron weighs about 1 amu an electron on the other hand is much much much smaller than a proton or neutron it weighs only 0.0005 for naught amu so a tiny fraction of how much our proton or a neutron weighs for this reason when we're talking about the mass of
atom
s which we'll talk about later on we usually add up the protons and neutrons to find out how many am use um theatom
weighs and then we usually don'teven worry about the electrons at all because they're just they're so tiny they don't really have much of an influence on how much an
atom
weighs it's like when you get on a scale to weigh yourself you don't worry about the ring you're wearing or whether you're wearing a necklace or something because those things are just so tiny they weigh so little compared to how much you weigh that it doesn't really influence your weight so protons and neutrons 1 amu andelectrons a tiny fraction of that now I send to the
atom
the way it's drawn here isn't a perfect representation of whatatom
s would actuallylook
like we'll talk more about that later but there are two things that I want to yup for right now the first is the electrons and how they move this drawing might make you think that the electrons are spinning around in Nice circles on the outside of theatom
that's actually not what happens they're buzzing around much more randomlykind of like hyperactive flies all over the place we'll talk more about that later the second thing has to do with the size of the nucleus and how far the electrons are from it if this were a real
atom
blown up many many times and the nucleus were the size of a grape the electrons out here would be almost a mile away so have this grape sized nucleus and a mile away would be the electron spinning on the outside so that means that most of anatom
is actually empty space anyway now thatwe've talked about what an
number mass number and net charge