Transcript Elements and compounds

Elements, Compounds
and Molecules
They “Matter”!!!!
What is MATTER?
Matter is anything that has mass,
occupies space, and is convertible to
energy
*Matter has two types of properties:
Physical and Chemical
Physical Properties of Matter
• Can be observed with the 5 senses
• Can be determined without destroying the
object
• Examples: color, shape, mass, length, odor ,
density, solubility, taste, melting point,
hardness, boiling point, luster, texture
Chemical Properties of Matter
• These indicate how a substance reacts with
something else.
• The original substance is fundamentally
changed while observing a chemical
property
• Examples: rusting (oxidation),
flammability, reactions with other
substances such as acids or bases,
combustibility,
WORKSHEET!!!
CAN I HEAR AN “OH YEAH!”
Take a few moments to fill out the
“Physical VS Chemical Properties”
worksheet!
What are elements?
Elements are pure substances.
This is because they cannot be broken down into
simpler substances.
They cannot be made by combining other
substances either.
Examples of Elements
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 same.
Element Symbols
Each element in the periodic table is
represented by a symbol of one or two letters.
These letters (symbols) come from the English,
Latin or Greek name for the element.
The first letter is always a CAPITAL and the
second letter (if there is one) is always
lower case.
Elements and the Periodic Table
The elements are organised and presented
in the Periodic Table.
The Periodic Table displays the following
information about an element:
•
•
•
•
Symbol
Name
Atomic number
Atomic weight (not always)
Atomic number
Element symbol
Element name
Atomic weight
Now lets diagram the parts of an element on
the periodic table!
Question…
How can only 92 naturally occurring
chemical elements form millions of
different types of materials?
What are compounds?
Compounds are formed when two or
more different elements
chemically combine.
This process is called a chemical reaction.
The new compound formed has different
properties from the original elements.
Compound: Water
Water forms through the following reaction:
Element
Element
Compound
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:
Compound: Water
2 atoms of
Hydrogen
1 atom of
Oxygen
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 molecule is
formed.
The atoms are tightly joined.
These bonds between atoms
in a molecule are called chemical bonds.
These chemical bonds cannot be easily broken.
More about molecules
Molecules that are
elements:
Atoms are the same
Molecules that are
compounds:
Atoms are different.