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Inquiry Lab
Stations
Particles of Matter
http://mypuzzle.org/color-link-a-pix-volume-2
Atoms
https://www.youtube.com/watch?v=R1RMV5qhwyE
• Atoms are the general term used to describe pieces of
matter
• Matter is composed of atoms. Solids are made of
densely packed atoms while gases have atoms that are
spread out.
• Are there pieces of matter that are smaller than
atoms?
Sure there are. Super-small particles can be found inside the
pieces of atoms. These subatomic particles include nucleons
and quarks. Nuclear chemists and physicists work together at
particle accelerators to discover the presence of these tiny,
tiny, tiny pieces of matter. However, science is based on the
atom because it is the smallest distinct unit of matter.
Three Easy Pieces
Even though many super-tiny atomic
particles exist, you only need to remember
the three basic parts of an atoms:
electrons, protons, and neutrons.
What are electrons, protons, and
neutrons?
• Electrons are the smallest of the three
particles that make up atoms.
• Electrons are found in shells or orbitals
that surround the nucleus of an atom.
• Protons and neutrons are found in the
nucleus. They group together in the
center of the atom. That's all you have
to remember. Three easy pieces!
~ There are almost 120 known
elements in the periodic table.
Chemists and physicists are
trying to make new ones
every day in their labs.
~ The atoms of different
elements have different
numbers of electrons,
protons, and neutrons.
~ Every element is unique and
has an atomic number. That
number tells you the number
of protons in every atom of
the element. The atomic
number is also called the
proton number.
Charges of Atoms
You can see that each part of the
atom is labeled with a "+", "-", or a
"0." Those symbols refer to the
charge of the particle.
Have you ever heard about getting
a shock from a socket, static
electricity, or lightning? Those are
all related to electric charges.
Charges are also found in tiny
particles of matter.
http://www.youtube.com/watch?v=TCUK93s1jUY
Always Moving
• As you know, electrons are always
moving.
• They spin very quickly around the
nucleus of an atom. As the electrons zip
around, they can move in any direction,
as long as they stay in their shell.
• Any direction you can imagine —
upwards, downwards, or sideways — electrons can do it.
• Electrons are constantly spinning in
those atomic shells and those shells, or orbital's, are specific distances
from the nucleus.
• If you are an electron in the first shell,
you are always closer to the nucleus than the electrons in the second
shell.
Charge It
• Electrons are the negatively
charged particles of atom.
• Together, all of the electrons of
an atom create a negative charge
that balances the positive charge of
the protons in the atomic nucleus.
• Electrons are extremely small
compared to all of the other parts of
the atom. The mass of an electron is
almost 1,000 times smaller than the
mass of a proton
Actual atoms of Graphite
Shells and Shapes
~ Electrons are found in clouds that surround the nucleus of an atom.
~ Those clouds are specific distances away from the nucleus and are
generally organized into shells.
~ Because electrons move so quickly, it is impossible to see where they are at
a specific moment in time. After years of experimentation, scientists
discovered specific areas where electrons are likely to be found.
~ The overall shape of the shells changes depending on how many electrons
an element has.
~ The higher the atomic number, the more shells and electrons an atom will
have. The overall shell shape will also be more complex (because of the
suborbitals) as you have more electrons
Creating Bonds
~ Electrons play a major role in all chemical bonds.
~ There is one type of bonding called electrovalent
bonding (ionic), where an electron from one atom is
transferred to another atom.
~ You wind up creating two ions as one atom loses an
electron and one gains one.
~ The second type of bonding is called covalent bonding,
where electrons are actually shared between two or
more atoms in a cloud.
~ Both types of bonds have specific advantages and
weaknesses
Power Up
~ Electrons are very important in the world of electronics.
~ The very small particles can stream through wires and
circuits, creating currents of electricity.
~ The electrons move from negatively charged parts to
positively charged ones.
~ The negatively charged pieces of any circuit have extra
electrons, while the positively charged pieces want
more electrons. The electrons then jump from one
area to another. When the electrons move, the current
can flow through the system.
Ions
The atomic number of an element, also called a proton
number, tells you the number of protons or positive
particles in an atom.
A normal atom has a neutral charge with equal numbers
of positive and negative particles. That means an atom
with a neutral charge is one where the number of
electrons is equal to the atomic number.
Ions are atoms with extra electrons or missing electrons.
When you are missing an electron or two, you have a
positive charge. When you have an extra electron or
two, you have a negative charge.
What do you do if you are a sodium (Na) atom?
You have eleven electrons — one too many to have an entire
shell filled. You need to find another element that will take
that electron away from you. When you lose that electron,
you will you’ll have full shells.
• Whenever an atom has full shells, we say it is "happy."
Let's look at chlorine (Cl). Chlorine has seventeen electrons
and only needs one more to fill its third shell and be "happy.“
Chlorine will take your extra sodium electron and leave you
with 10 electrons inside of two filled shells. You are now a
happy atom too. You are also an ion and missing one electron.
That missing electron gives you a positive charge. You are still
the element sodium, but you are now a sodium ion (Na+). You
have one less electron than your atomic number.
Electrovalence is just another word for something
that has given up or taken electrons and become an
ion.
If you look at the periodic table, you might notice that
elements on the left side usually become positively
charged ions (cations) and elements on the right
side get a negative charge (anions).
That trend means that the left side has a positive
valence and the right side has a negative valence.
Valence is a measure of how much an atom wants to
bond with other atoms. It is also a measure of how
many electrons are excited about bonding with
other atoms.
Isotopes
Neutrons play a major role in the mass and
radioactive properties of atoms. Isotopes are
created when you change the normal number of
neutrons in an atom.
You know that neutrons are found in the nucleus of an atom.
Under normal conditions, protons and neutrons stick
together in the nucleus.
During radioactive decay, they may be knocked out of there.
Neutron numbers are able to change the mass of atoms,
because they weigh about as much as a proton and
electron together. If there are many atoms of an element
that are isotopes, the average atomic mass for that
element will change.
We have spoken about carbon (C) having an average mass of
12.01. It's not much different than you would expect from
an atom with 6 protons and 6 neutrons. The number of
carbon isotopes doesn't change the atomic mass very
much. As you move higher in the periodic table, you will
find elements with many more isotopes.
Compound Basics
• Molecule is the general term used to describe any
atoms that are connected by chemical bonds.
• Every combination of atoms is a molecule.
• A compound is a molecule made of atoms from
different elements. All compounds are molecules,
but not all molecules are compounds.
• Hydrogen gas (H2) is a molecule, but not a
compound because it is made of only one element.
Water (H2O) can be called a molecule or a
compound because it is made of hydrogen (H) and
oxygen (O) atoms.
When we discuss phase changes in matter, we are
looking at physical changes.
Physical forces alone (unless you're inside of the
Sun or something extreme) rarely break down
compounds completely.
You can apply heat to melt an ice cube, but there
will be no change in the water molecules. You
can also place a cup of water in a container and
decrease the pressure. The water will eventually
boil, but the molecules will not change.
Chemical changes in compounds happen when
chemical bonds are created or destroyed.
Forces act on the bonds between atoms, changing
the molecular structure of a substance.
You can pour liquid acid on a solid and watch the
solid dissolve. That process is a chemical change
because molecular bonds are being created and
destroyed. Geologists pour acids on rocks to test
for certain compounds
Naming Compounds
• When you have two different elements, there are
usually only two words in the compound name.
• The first word is the name of the first element.
• The second word tells you the second element and
how many atoms there are in the compound.
• The second word usually ends in IDE. That's the suffix.
• When you are working with non-metals like oxygen (O)
and chlorine (Cl), the prefix (section at the beginning of
the word) of the second element changes based on
how many atoms there are in the compound. It's like
this...
(1) Carbon + (1) Oxygen = Carbon monoxide (CO)
(1) Carbon + (2) Oxygen = Carbon dioxide (CO2)
(1) Carbon + (4) Chlorine = Carbon tetrachloride
(CCl4)