In this video you're going to learn everything you need to know about atomic structures and
chemical symbols. Alright let's do this
[Music Playing]
Hello Hello Melissa Maribel here and I
help students like you understand what
you just learned in class so you stress
less and you graduate faster. Let's talk
about atoms, my friend John Dalton over
here came up with the theory that
everything is composed of atoms.
Random Man: Everything, even this? Melissa Maribel:  Let's see, let's see, hmm.. yeah yeah
Those are atoms alright, mm.. hmm.. mm.. hmm..
Random Man: What about this? Melissa Maribel: Huh let me see, oh gosh no! Yes, yep those are atoms, those were atoms. mm.. hmm..
Random Man: Even these two? Melissa Maribel: Literally Adams
Okay Okay
but what makes up an atom? What makes up
an atom are three different types of
particles protons, neutrons and electrons
protons are positively charged, neutrons
have no charge or are known as neutral
electrons are negatively charged. Let's
look at the set up for a chemical symbol
the X represents the chemical symbol or
the element. A is the mass number Z is
the atomic number. For example our
potassium or K has a mass number of 39
an atomic number of 19. On the periodic
table that 19 or atomic number is on top
your atomic mass is on the bottom. Let's
talk about the difference between an
atomic mass and a mass number. A mass
number is our protons plus our neutrons
versus the atomic mass is the average of
all the different types of isotopes of
that element. We will discuss isotopes in
a separate video in a neutral compound
like potassium just meaning there is no
charge your atomic number protons and
the electrons are all equal and we see
that each one of those is 19. To figure
out how many neutrons you have take the
atomic mass and subtract that by your
protons.
Subtracting these two numbers will give
you 20 neutrons. Let's talk about ions
ions are elements with a charge.
Phosphorous has a charge of negative 3
let's figure out our atomic number and
how many protons there are. Looking at
your periodic table let's figure out
where phosphorous is then the atomic
number will be on top your atomic number
is equal to the same amount of protons
so our atomic number and protons will
both be 15 if we're trying to figure out
how many neutrons you take your mass
number or atomic mass which will round
to 31 and subtract it from the total
amount of protons that then gives you 16
neutrons to figure out your electrons
take your proton count and subtract it
from the total charge our charge was a
negative 3 these two will then multiply
becoming a positive so we'll have 15
plus 3 giving us 18 electrons what you
could have also seen was since this is a
negative 3 charge this is gonna add to
the amount of electrons because
electrons are negatively charged so
they're becoming more negative. Let's
look at our next example with an ion
with a positive charge. Phosphorus now
has a 3 plus charge we're still going to
figure out our atomic number, atomic mass,
protons, neutrons and electrons, however
our atomic number and proton count will
not change neither will our atomic mass
we'll also round it to 31 and our
neutrons will still be the exact same
our electrons are the only thing that
changes so we'll take our protons and
subtract it from our total charge of 3
and that will give us 12 once again
our charge is a positive 3 so this is
actually going to subtract from our
electrons since electrons are negatively
charged now what if you're given the
amount of protons, neutrons and electrons
and you're asked to figure out is it a
neutral element or is it an ion.
Determine the element or ion
that has 26 protons, 30 neutrons and 29
electrons. Here's a trick on figuring out
if it's a neutral element or if it's a
charged element which is an ion if your
protons and electrons are equal to each
other that means it is neutral, if your
protons and electrons are not equal to
each other that means it is an ion in
this case our protons and electrons are
not equal to each other that means it
will be an ion. First off our atomic
number is the same amount of protons so
we know that it is 26. Looking at your
periodic table let's look for the atomic
number of 26 as you can see it is Fe
also known as iron. If you are asked to
figure out the mass number you would add
your protons plus your neutrons that
would then give you 26 plus 30 which is
56 to figure out your charge take the
atomic number or proton count and
subtract that by your total amount of
electrons 26 minus 29 gives us a
negative 3 charge we have iron with a
negative 3 charge this is our final ion.
Get ready for some practice problems hit
it Johnny
[Music Playing]
I hope you got everything right as
always I've linked up practice problems with
step-by-step answers in the description
box below let me know what you're
struggling with if you have a homework
problem that you don't quite understand
leave a comment and I'll answer it and
I'll see you next time. Alright let's do
this. [Laughs]
Well, that was it, no more takes
What's going on in there? It's a popping!
Okay I'm done
