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Well it's another
time to do a little bit of notes
so if you would please,
get out a piece of paper. You're going to title it 6.1
Atoms, elements, and compounds
so if you put that as a title of your paper
that would be good so 6.1
Atoms, elements, and compounds. Now
I just put up here the structure of this
section so it has your blue headings and your red subheadings
so these are the main ideas that we're going to be talking about
am I gonna go over every detail? no, but we're going to give you the basics so
that when you do
read it it will help you make more sense. Now at the bottom here it says do
Ch 6.1 packet together, no that's part of your homework
so when you're done listening to these notes, you want to open up the packet at
my website
downloaded into PDF notes and answer the questions and then save it to Showbie.
to 6.1. So let's get started
I want you to write this down this chart
Not everything I'm gonna have you write but there are certain things
so this is atoms versus molecules.
Here we have atoms and
make in an arrow and show that it goes
to the word element. When we have groups of like
atoms, we call them an element. We sometimes call these families.
So when we have a group of like atoms, we call it an
element. Normally we represent this by using symbols
and you're familiar with quite a few symbols so here are some examples:
C stands for
and if you thought carbon, you were correct.
H would be hydrogen
Cl is chlorine
and Na? You may not be familiar with this one.
This happens to be sodium but the S was already used so they went to the Latin
word
of natrium and they use the Na from natrium
but each of these are a symbol
that represents one atom. Now if you come back up here to the word
element and then you
add another element.. then we're going to end up with
a compound. Now can be 2 or more
elements but I just put 2 here, so element plus
element will make a compound. The smallest unit of a compound
is a molecule. And I'm going to talk about the chemical change here in just a
minute. Now since we represent elements with symbols, we're going to represent
compounds with what we call chemical
formula. It's almost a chemical recipe
and one that we're very familiar with this H2O
which stands for water. If you notice here we have 2
hydrogen atoms, one oxygen
atom and when we combine this together we have a molecule of
water so that's the recipee or formula:
two hydrogens + one oxygen. If you notice
if I were split this in half I would have hydrogen which is a gas
I would have oxygen which is a gas
but when we combine them together to make a compound, they
chemically change and this becomes liquid
or water. Another one you are going to come to
love is called C6 H
12 06, six carbon atoms 12 hydrogen atoms
6 oxygen. This happens to be
the molecule glucose and our body
runs and glucose so you'll be hearing about this a lot more.
I wanted to also show you what happens when we put a number
in front a this atom excuse me
not atom but this molecule. This says how many molecules of water I have
so here I have four molecules of water
so how many atoms do I have in 4 molecules.
Well you would take 4 times 2 or 8 hydrogen
four times one or 4 oxygen.
So whenever there's a number in front it just tells
how many atoms, oops, how many molecules
there are of this compound.
We have one molecule, one molecule,
4 molecules. This is the easiest way to compare
atoms, elements, molecules, and compounds.
So be sure you can explain this chart
and you should have it written down in your notes.
The next screen we're going to talk about: what makes up in
atom. So as you know the center of an atom
is the nucleus and inside the nucleus we have
positive charges and you're probably wondering if you need to write this down
and let's go ahead and draw this picture.
I apologize for not saying that so go ahead and make a circle,
title at nucleus, then put two circles
inside with plus signs and you probably remember these
as protons so those are the positive charges.
Sometimes we also find
neutral particles called neutrons
and those can be found in the nucleus.
Going around the nucleus we have energy levels
and in the energy levels we find another particle
that happens to be negative. These are called
electrons. In order for this atom
to be neutral, we have to have the same number of protons
as electrons so they balance each other out.
What's interesting, atoms always like to fill their electrons from the
innermost energy level outward.
So we always have 2 electrons in the first energy level
then it's full. If there are still more electrons, they go to the second energy
level which is full with
8. So that just leads us into our next topic
so this is an atom and its structures.
We also want to show a structural formula.
You do not have to draw this one. Just listen and watch.
A structural formula show how the atoms
are arranged. These lines represent a bond
and the bond is what holds these atoms together.
Also if you were to break a bond, it releases energy.
So this happens to be the structural formula of water.
This next picture is going to talk about an isotope.
If you notice, there are three
isotopes of hydrogen. Each
of the hydrogens have one proton.
What makes them different is the number of neurtons that they have.
So these are all hydrogen but different forms
or isotopes because of the number of hydrogens.
no hydrogens, oops wrong word...
no neutrons, one neutron,
two neutrons. So what is an isotope?
its a form
a an atom that differs in neutrons.
We're going to go on to our next screen that happens to do with
bonding. We have three types of bonding that we're going to talk about.
If I run out of time, I may need to do another part
2 here, I think we're doing okay so far.
I want you to notice here sodium has
11 protons so therefore it has
in 11 electrons. We're going to fill the
inner most energy level first, so we have 2
in our first energy level.
The next energy level is filled with 8
so 2 + 8 = 10. That leaves 1 electron
in the outermost energy level. Chlorine on the other hand
has 17 protons. So again we fill the first energy level with two electrons.
The next energy level with 8 electrons so
that makes 10 total and we have 7 more to go
in the next energy level. The thing is
its full with 8, so if it had one more
it would be full. atoms like to have a full
outer energy level so anytime sodium and chlorine
are next to each other,sodium
doesn't like to have one lonely electrons stuck out there
so it gives it away to the chlorine.
Chlorine wants its outer energy level to be full so it takes it.
Now sodium has a full outer energy level.
Chlorine has a full outer energy level. But now we're going to have some charges.
When we used to be neutral but if I give away a negative,
it means that sodium is a little bit
positive because chlorine takes
on the negative, it becomes a little bit negative
and whenever you have a positive and negative together they attract each
other
and we call that an ionic bond.
Because these are now charged atoms
and on this slide I want you to write what an ionic
bond is or I should say to write the word ionic bond
and then also write ions equal charged
atoms.
I also want you to write the example. When we have sodium that's
positive and chlorine that's negative,
the positive and negative attracts creating this ionic bond.
So this is an ionic
bond. The next we are going to go see
and I want you to write the word covalent bond.
co means to share. So here we have hydrogen.
It has this one has one proton + one-electron.
To be full, it needs to have 2 electrons.
So anytime hydrogen is near each other, they share their electrons
so both of them feel like they have a full
outer energy level. Because they zoom around both
of the protons so this sharing creates a bond
that we call call covalent. So underneath the word covalent, I want you to
write
atoms share electrons.
We're going to go on to the next screen and I want you to write down
vander walls forces.
If you've ever seen an insect walk on water,
vander walls forces is going to help explain this.
We're going to show, in a way, a structural formula
of water. This bigger one represents
oxygen and these two smaller ones represent hydrogen.
Two hydrogens and one oxygen. I want you to notice how big the oxygen is
in relation to these itsy bitsy
hydrogen atoms.
Notice we have 8 protons and 8 electrons. 1st 2 fill the inner energy level with leaving
six in the next. Two are needed to have a full
outer energy level. The hydrogen
only have one and they want to share so what happens is
these little ones go up and around the oxygen and come back down. They share
their electrons with the oxygen.
But think of this as the earth and these as 2
little moons. This has a lot more pull:
so this little electronic spends more time around the
oxygen making this end a little bit negative.
Since this electron up here more often,
it makes this end a little bit positive.
So we call water molecules polar
because they have 2 different poles.
Well if I have another water molecule nearby
noticed this negative end is attracted to this positive end
that is van der Waals forces.
In other words, water molecules become kind of sticky.
They are attracted to each other. This positive end is attracted to this
negative
end and it creates a bond. It is a weak bond that holds water molecules together
and therefore it makes water so it sticks together so that insects being so
lite
can walk on water. So on this, I really don't need you to write anything
but I want you to understand what it is.
Now I have just a minute left so here's what I want you to do.
on page 149 figure 6.3
there's a question there next to the word interpret
I want you to read and interpret and put the
answer to that question in a box at the end of your notes. Just put the answer
and put a box around it
and we'll see everybody later! Thank you! Good job!
bye bye