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Earth Chemistry Guided Notes
Matter
Anything that _______________________________________________________________________
All matter has two types of properties—___________________ and___________________
PHYSICAL PROPERTIES OF MATTER
Characteristics that can be observed ___________________substances’ composition
EX: density, color, hardness, freezing point, boiling point
CHEMICAL PROPERTIES OF MATTER
Characteristics that describe how two substances___________________ to produce new substances
Rusting, burning, reaction with acid or base
What are elements?
Elements are ___________________
___________________.
This is because they cannot be broken down into simpler substances.
They cannot be made by combining other substances .
How many elements?
There are 117 known elements.
92 of the elements can be found in the Earth’s rocks, soil, air and water.
The remainder have been made by nuclear scientists.
Atoms and Elements
If you could look at the atoms in a chemical element you would see that they are all the same type.
For example: If you had a sample of Hydrogen, you would see that all of the atoms looked exactly the
___________________
Element Symbols
Each element in the periodic table is represented by a symbol of ______________________________.
These letters (symbols) come from the English, Latin or Greek name for the element.
The first letter is always a ___________________ and the second letter (if there is one) is always
___________________
Elements and the Periodic Table
The elements are organized and presented in the ______________________________________.
The Periodic Table displays the following information about an element:
• Symbol
• Name
• Atomic number
• Atomic weight (not always)
Parts of Elements on the Periodic Table
___________________
___________________
___________________
___________________
COMPOUNDS
What are compounds?
Compounds are formed when two or more different elements ___________________ combine.
This process is called a ___________________ ___________________.
The new compound formed has different properties from the original elements.
Compound: Water
Water forms through the following reaction:
More about compounds
Compounds always have the same ratio of elements.
For example: Water always contains two atoms of hydrogen to one atom of oxygen.
For this reason, water has the chemical formula:_________________
How do elements and compounds exist?
Some chemical elements, such as gold, mercury, helium, and neon are found in nature as single atoms.
Others such as hydrogen, oxygen and nitrogen can be found with more than one atom (the same type
of atom) joined together.
Molecules
When two or more atoms join together (the same or different atoms) a ___________________ is
formed.
The atoms are tightly joined.
These bonds between atoms in a molecule are called ___________________ ___________________
These chemical bonds cannot be easily broken.
More about molecules
Molecules that are
___________________:
Atoms are the same
Molecules that are
___________________:
Atoms are different.
ATOMS
Atoms are the ___________________ ___________________of matter
~ 1 million lined up side by side = thickness of 1 piece of paper
Atoms contain subatomic particles:
electron
•
___________________ (+ charge)
•
___________________ (neutral)
•
___________________ (- charge)
neutron
proton
Here’s an idea of the mass of these particles!!!
ATOMIC STRUCTURE
Protons have a___________________charge and neutrons have ___________________charge
Protons and Neutrons are located in the ___________________, which ends up with a positive charge
due to the protons
___________________—space around nucleus containing electrons
Draw a hydrogen atom below and label it
ATOMIC NUMBER
Number of protons in the nucleus—found as upper # in box
There are ___________________ #s of protons and electrons in an atom, therefore, this is also the
number of electrons
Elements are ordered on the periodic table in order of their _________________ ________________
How many PROTONS are there in…
Hydrogen? ___________________
Silicon? ___________________
Lead? ___________________
Barium? ___________________
How many ELECTRONS are there in…
Fluorine? ___________________
Carbon? ___________________
Sodium? ___________________
Copper? ___________________
MASS NUMBER
Sum of # of protons & neutrons is ___________________
___________________
If you know the number of protons (atomic number) and number of neutrons, you can determine the
mass number
This is close to the atomic mass--# at the bottom of the box
Determine the MASS NUMBER and element names
Protons = 6, neutrons = 6,
Mass # =___________________
Protons = 9, neutrons = 10,
Mass # =___________________
Determine the number of NEUTRONS and the element name
Mass number = 14, protons = 7,
Neutrons =___________________
Mass number = 73, electrons = 32
Neutrons =___________________
Diagramming Atoms
A diagram of an atom is just a simple drawing of the atom’s ___________________
First, determine how many protons, neutrons and electrons the atom has.
Then, diagram it, using:
a circle w/ a plus sign for protons
circle w/ a minus sign for electrons
+
-
a blank circle for neutrons.
Make sure these are located in the correct places!
Diagramming Atoms
Lithium, Mass # = 7
Protons = 3, Electrons = 3, Neutrons = 4
Diagramming Atoms
Carbon, Mass # = 12
Protons = 6, Electrons = 6, Neutrons = 6
Diagramming Atoms
Boron, Mass # = 11
Protons = 5, Electrons = 5, Neutrons = 6
Sum it up so far…
Definition: Compounds are formed when two or more different elements ___________________
combine.
A ________________________ is the smallest physical unit of a substance that can exist independently,
consisting of one or more atoms held together by chemical forces
____________________ _____________________ tells what elements and how many of each atom
make up the compound
H2O—2 hydrogen atom, 1 oxygen atoms
NaCl—1 sodium, 1 chlorine
CH4??? ______________
NO2??? ______________
H2SO4??? ______________
CHEMICAL EQUATIONS
Chemical Equations: ___________________________________________________________________
____________________________________________________________________________________
CH4 + 2O2  CO2 + 2H2O
Reactants on left, products on right of the arrow
BALANCING
Chemical equations must be balanced—this means an ___________________ number of each atom on
both sides of the arrow—use coefficients (#s in front of the compound of element)
IONS
Ion = an atom that has an electric charge by______________or _____________one or more electrons.
Charges show if the atom has gained or lost an electron:
—positive (_________________) means electrons lost
—negative (_________________) means electrons gained
Na+--sodium with 1 less electron
Cl---chlorine with 1 extra electron
ANIONS VS CATIONS
Cation--An atom or a molecule which is positively charged, i.e. has ________________
________________ than electrons. Metals.
Ex: sodium (Na+), Iron (Fe2+), and Lead (Pb2+)
Anion--An atom or a molecule which is negatively charged, i.e. has ________________
________________ than protons. Non-metals
Ex: iodide (I-), nitride (N3-) and hydride (H-)
Determine how many extra/less electrons the following atoms have:
Al3+ = ________________ cation or anion?
I- ___________________ cation or anion?
OH- _________________ cation or anion?
CHEMICAL BONDS
These are forces that hold atoms ___________________
Formed by ___________________ or ___________________ electrons between atoms
TYPES OF BONDS
Ionic bonds—forms between a metal and nonmetal—
electrons___________________
Covalent bonds—forms between two nonmetals—electrons
___________________
Are these ionic or covalent compounds?
CO2
_____________________—both are nonmetals
LiBr
_____________________—Li is metal, Br is nonmetal
NaCl
_____________________—Na is metal, Cl is nonmetal
PCl3
_____________________—both are nonmetals
MIXTURES
A mixture is a substance consisting of two or more substances that have been combined without
chemical bonding taking place
Heterogenous mixture—________________________________________________________________
Homogenous mixture—________________________________________________________________