Transcript Elements, Compounds and Mixtures

Elements, Compounds
and Mixtures
Elements are substances
that cannot be separated
into any other substances
by chemical or physical
means
A pure substance
is only ONE type of
element.
Elements are
organized by their
properties on the
Periodic Table of
Elements
Periodic Table of the Elements
Period (Rows) numbers are listed on the left hand side of the Periodic Table
and apply to all the elements in the row that follows it.
1
2
3
4
5
6
7
• Group (Families) numbers are listed at the top of the periodic table and
apply to all the elements in the column below it.
18
1
2
13
14 15
16 17
Elements are
represented by
chemical symbols.
st
1
Letter is always
capitalized. If it
nd
has a 2 letter it
is NOT capitalized.
An atom is the
smallest particle
of an element
(smallest unit)
Examples:
H = Hydrogen
He = Helium
Ca = Calcium
C = Carbon
Au = Gold
O= Oxygen, O2 = Oxygen we
breathe, O₃= Ozone
A compound is made
of TWO or MORE
different elements
chemically combined
in a set proportion or
ratio.
Compounds undergo a
chemical change when the
elements bond together.
The properties of the
compound are DIFFERENT
than those of the elements
that made it.
Compounds
are
represented by
formulas
Subscripts are small lowered
numbers that follow a chemical
symbol.
Example: H2O (2 atoms of
Hydrogen, and one atom of
Oxygen)
The subscript represents the
number of atoms of the element
which are present. No subscript = 1
Examples:
Water H₂O
Sugar C₆H₁₂O₆
Salt NaCl
Carbon Dioxide CO₂
Mixtures are a substance
that is made of two or
more substances
(elements, compounds
or both), but are NOT
chemically combined.
The components
can be separated
back out by
physical means.
Examples:
Sea Water
Soil
Soda
Salad
Gases in the atmosphere
A solution is a special kind of
mixture where one substance
is dissolved in another
substance.
Ex: salt water, Kool-Aid
This is a PHYSICAL CHANGE.
.