A sound understanding of atomic structure is essential to unlocking the predictive nature
of chemistry and the reactivity of elements. If we think about the subatomic structure
we need to think about those parts of the atom: protons, neutrons and electrons. If
we think about a structure there were a lot of attempts to try to explain an atom. There
was a pudding model. There was a simple solar model by Rutherford but it really didn't crystallize
until Bohr added quantum theory to the value. With the Bohr model we have a nice simple
model that works. The sad part is it only works with hydrogen with one electron but
it is still a great way for us to look at atom's structure interestingly Bohr actually
along with Heisenberg set up the experiment that disproved his own model. Later on they
came up with quantum mechanics much more complex system to look at the atom's structure but
is the current and best way to calculate atomic structure. Thinking about the Bohr model when
you think about the subatomic particles and where they are so using the simple Bohr model
we can really think about it as we would a solar system. For the sun we have the nucleus
for this planets we have electrons. In the nucleus we have protons and neutrons the protons
are essential. The protons give us what element we every actually have so if we think about
the number of protons if we have one proton it's a hydrogen, if we have six protons its
carbon. This is the atomic number and it gives us the element if we think about neutrons,
neutrons can be added to the nucleus but add changing the number of neutrons does not change
the element. So if we have zero neutrons in a hydrogen it be it is hydrogen one or our
normal hydrogen if we have one neutron all of a sudden it is hydrogen two or deuterium
if we have two neutrons it is now hydrogen three or tritium. If we think about carbon
we have the same thing if we have carbon it's gonna have six protons if it didn't has six
protons it wouldn't be carbon. We can have six neutrons in carbon and that'll make carbon
twelve if we have seven neutrons carbon thirteen. These are isotopes. We have different isotopes
that have different masses. If we look at the last subatomic particle electrons, electrons
want to balance protons. In a neutral atom you will have the same number of protons as
you have electrons. Electrons have very little mass so therefore they do not add to the overall
mass of a molecule. Therefore they do not add to the mass of an atom. If we think about
the electron if it's balanced in the case of hydrogen, hydrogen has one proton so we
would have one electron. If we have hydrogen with no electrons than that hydrogen would
have a positive charge because we do not have a proton with a positive and an electron with
a negative balancing each other. If we had two electrons in hydrogen that only has one
proton than we would have a negative one charge. When we look at this structure the electrons
are really what's going to be giving us our reactivity and knowing the balance of electrons
to protons can tell us the ion. If we have a positive charge as in hydrogen plus that's
gonna be a cation if we have a hydrogen negative one extra electron then that's gonna be an
anion. We're gonna use these two to help predict the reactivity of the elements. We're gonna
take this understanding of atomic structure build on it through throughout the course
and we're going to look at how it is embedded into the periodic table.