Download Review… Identifying Char. Of Elements

1. Elements
The Nature of Matter
Elements and compounds make up all the different kinds
of matter in the universe.
Matter is anything that takes up space and has mass.
The word matter comes from the Latin word materia,
meaning “material” or “stuff”
Elements are the simplest form of matter
Examples of Matter:
You can observe matter easily with your senses . . .
rocks, trees, bicycles, air . . . Basically everything
and anything!

Cannot be broken down into simpler substances.

Each element is made of atoms of the same type.

The only thing that wouldn’t be matter would be
energy (sunlight, heat, electricity).
- no mass or volume so they can’t be matter!
Each has a unique set of physical and chemical
properties.

117 known elements in the universe.

Approximately 92 are found naturally on Earth.
Review…
• An atom is made up of
• Protons – positively charged, mass of 1
• Neutrons – no charge, mass of 1
• Electrons – negative charge, mass of 0
Six elements make up 99% of all living matter!
• Nitrogen
• Sulfur
• Carbon
• Potassium
• Hydrogen
• Oxygen
Identifying Char. Of Elements
• Atomic number: number of protons
in the nucleus of each atom of
that element
12
Atomic
Number
C
• Isotopes: 2 elements that have the same
atomic number, but different mass numbers
• SAME number of PROTONS but DIFFERENT
number of NEUTRONS
• Mass Number= number of protons plus the
number of neutrons for the specific isotope.
6
6
12 6
Protons:
Neutrons: 6
Mass #: 12
Electrons: 6
Atomic
Number
6
Protons:14
6
Neutrons: 8
Mass #: 14
Electrons: 6
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• Atomic Mass: The average mass of all of the
naturally occurring isotopes for the element
• Found on the periodic table
Classifying Elements
• 3 different classifications
1. Metals
2. Nonmetals
3. Metalloids
Chlorine
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35.435
1. Metals
• Shiny metallic luster
• Good conductors of heat & electricity
• All metals (except mercury) are solids at room
temperature.
• Malleable: can be bent/pounded into different
shapes
• Ductile: Can be made into wires without
breaking
3. Metalloids
•
•
•
•
Have characteristics of metals/nonmetals
Solids at room temp
Good conductors, not as good as metals
Used to make electric circuits in Televisions,
computers, and other electronic devices.
2. Nonmetals
• Dull in appearance
• Poor conductors of heat & electricity
• Gasses at room temp
• Except Bromine (liquid)
• Brittle: cannot change shape easily w/o
breaking
• 97% of your body
2. Molecules
When two or more atoms combine,
they form a molecule.

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Most molecules are made of two or
more atoms
A molecule is the smallest particle
of a substance with the same
properties of the substance.
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Matter that has the same
composition and properties
throughout are called
SUBSTANCES.
1. Compounds
Compounds are two or more elements
bonded chemically together.

(compounds, mixtures, or
solutions)

Properties are different from the
properties of the elements that make
them up.
Have Formulas
• Formulas tell you what elements make up the
compound.
• The number of each element that is in the
compound is written as a subscript.
• H2O = Water, made up of 2 Hydrogen and 1 Oxygen
element.
• H2O2 = Hydrogen Peroxide, made up of 2 Hydrogen
and 2 Oxygen.
# of Atoms of
each element
Properties of the Compound
H2O - Water
1 oxygen
2 hydrogen
Non-irritating liquid used for
bathing, hydration, cooking, etc.
H2O2 –
Hydrogen
peroxide
2 oxygen
2 hydrogen
Eye irritant, used to clean cuts.
Toxic to ingest.
2. Mixture
Most matter in the universe is in
the form of compounds!
A mixture is a combination of two or more
substances NOT combined chemically.
May be a mixture of both elements
and compounds

Substances keep their unique
properties and can be separated by
physical means.

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There are two types of mixtures . . .
Heterogeneous – the parts of
the mixture are noticeably
different from one another.
Homogeneous – the parts
(substances) are evenly
distributed. It is difficult to
tell one substance from
another.
3. Solutions
A solution is a mixture that looks like a single
substance and has the same properties
throughout.
Solute ~
The substance that dissolves in a
solution.
Solvent ~
The substance into which the
solute dissolves.
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