Download Elements PPT

Biogeochemical Cycles Second Semester Unit
Cycles we will cover this
semester.
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Rock Cycle
Star Cycle
And many
others.
Law of Conservation of Mass
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Matter cannot be create or destroyed, it
simply changes forms
Everything in the world cycles
Bottom line is there is a fixed amount of stuff
and we’re not making any more elements
Where they are located in the system effects
the system, how do we get the stuff we need
and how do we ensure that we have enough.
Matter
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Material that makes up everything in
our universe
All matter has mass and volume, it can
be weighed and take up space
Elements
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Pure substances that can not be
separated into simpler substances by a
chemical process
Known elements are found on the
periodic table of the elements
Atoms
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The smallest particle of an element. Atoms are very
small there is 10 to the 23rd atoms in a gram of water
Contain positively charged protons, neutral neutrons,
and negatively charged electrons
Neutrons and protons make up the nucleus of an
atom, while electrons orbit around the nucleus
Each element has a unique arrangement of protons,
neutrons, or electrons
Each element is unique
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Atomic number equals the number of
protons
The number of protons equals the
number of electrons
All elements (atoms) have a unique
arrangement
Periodic Table of the Elements
Atoms
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A stable atom has equal number of
protons and electrons
Each atom has electrons floating in
energy levels and there are patterns to
where those electrons are located
Oxygen Atom
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This atom has 8
protons.
That means that a
stable oxygen has 8
electrons.
In this oxygen atom the
first energy level can
hold two electrons, and
the second can hold
eight so it needs two
more to be stable, that
means that oxygen
wants to combine with
other elements or itself.
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1st
Energy
Level
2nd Energy
Level
Elements combine to make
compounds
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Most matter on Earth is
in the form of
compounds
Compounds have a
fixed ratio of atoms
Compounds contain
specific combinations of
elements, have the
same properties, and
react in predictable
ways
Bonding
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There are two types of chemical bonds
Covalent- in which atoms share
electrons so each has a full outer
energy level
Ionic- which one atom steals another’s
electron to fill its outer energy level and
in doing so creates opposite charges
which attract
Covalent Bonding
This Oxygen atom
will share the extra
electron so that their
valences are full.
Ionic Bonds
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Ionic bonds are created when an atom
with more proton pull steals an electron
from a weaker atom
When an atom gains or loses an
electron it becomes charged or ionized
What charge would an atom that loses
an electron have? Gains an electron?
Ionic Bonds
Elements are the building blocks
of our world.
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Elements combine to form compounds
Compounds combine to form
substances
One or more elements combine to make
minerals
Minerals combine to form rocks
Elements Vs. Atoms
NaAlSi3O8
How many elements are in this mineral? How
many atoms?
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KAl2(Si3Al)O10(OHF)2
How many elements are in this mineral? How
many atoms?
Minerals
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Minerals are naturally
occurring, inorganic,
solids, with a definite
chemical composition,
and an orderly
arrangement of atoms.
What a mouthful!
If we don’t grow it, it’s made
of minerals.
Look around the room and
make a list of all the things
made of minerals (Hint: if it’s
not wood it’s mineral)
Minerals
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We have joined two elements together with an ionic bond
to form the mineral Halite or more commonly salt.
Ionic Mineral Crystals
Na + Cl - Na + Cl - Na + Cl - Na + Cl -
Na + Cl - Na + Cl - Na + Cl - Na + Cl Na + Cl - Na + Cl - Na + Cl - Na + Cl -
Think in terms of a magnet. As opposites attract we
keep adding more molecules always positive to
negative as the crystal grows.