Download P Atoms and molecules.pps

Atoms and Elements
1. There are billions of materials in our
universe.
2. Those materials are made up from
about 100 elements only.
An element is a substance that is made
from one kind of atom only. It cannot
be broken down into simpler substances.
atom
An element
atom
An element
A substance made from only one type
of atom is a MOLECULE, and because
all the atoms are the same, it is still
an element.
Molecules can also be substances made from
more than one element. (These are also called
compounds)
atom
A molecule made up of 2
different elements
atom
A molecule made up of 7
different elements
A molecule that is a compound can be broken
down into elements
An element
An element
A molecule made up of 3
different elements
An element
Molecules
• A molecule can be made from the same type
of atom, or two or more different types of
atoms ( a compound)
• These can be broken down into individual
elements.
Chlorine Cl2
Methane CH4
Remember, all compounds are molecules but not all molecules are compounds
Chemical formulas
• These are used to represent molecules and
indicate the type and number of elements
that make up the molecule.
Rules for chemical symbols in the periodic table:
1. The symbol is usually the first one or two letters of the name.
2. Sometimes the old (Latin) name is used .
3. The first letter of a symbol is always a capital letter.
4. The second letter of a symbol is always a small letter.
5. Every element has a different symbol.
Numbers are used to represent how many
of each element are present in the
formula.
• The numbers are written to the right of the
element as a subscript (smaller and lower down)
H2O
• This tells us there are 2 atoms of hydrogen and
only 1 atom of oxygen.
What is a molecule?
A) Atoms separated by tiny spaces
B) Two or more atoms bonded together
C) Only ever made of the same type of atom.
D) Something that must always contain carbon
What is a molecule?
A) Atoms separated by tiny spaces
B) Two or more atoms bonded together
C) Only ever made of the same type of atom.
D) Something that must always contain carbon
How many of each atom are in the
following formulas.
• HCl
• Cl2
• CO2
• CH4
How many of each atom are in the
following formulas.
• HCl 1 hydrogen and 1 chlorine
• Cl2
• CO2
2 chlorine
1 carbon 2 oxygen
• CH4 1 carbon 4 hydrogen
Now look in your periodic table and find name that
corresponds to the following symbol:
Fe ……..
Mg ………..
Ag ………..
K ………..
C …………
Ca …….
Na ……….
N ………
Ne ……..
Pb ……….
Now look in your periodic table and find the symbols of the
following elements, then find out if it is a metal or a nonmetal:
Copper
Cu
Iron …Fe
Magnesium …Mg
Chlorine …Cl
Carbon ……C
Sodium …Na
Lead …Pb
Gold …Au
Calcium …Ca
Fluorine …F
Now look in your periodic table and find if each is a metal or a
non-metal:
Copper …………..
Iron ……………..
Magnesium ……………..
Chlorine ……………..
Carbon ……………..
Sodium ……………..
Lead ……………..
Gold ……………..
Calcium …………
Fluorine …………..
Now look in your periodic table and find out if each is a metal
or a non-metal:
Copper …metal
Iron …metal
Magnesium …metal
Chlorine …non-metal
Carbon …non-metal
Sodium …metal
Lead …metal
Gold …metal
Calcium …metal
Fluorine …nonmetal