Everything known in Science
(Universe)
Matter
• has mass ( measure of how much)
• has volume (takes up space)
Energy
•cause change / do work
Matter - always built from Atoms
Atoms – smallest complete units of matter
Atoms - made of 3 smaller (subatomic) particles
• Protons
• Neutrons
• Electrons
Nucleus = center
Helium atom
Periodic table of the Elements
Different atoms become the foundation for different elements
Periodic table of Elements?
Elements or Atoms?
Element
= a pure collection of the exact same type of
atoms.
Pure = only one type of atom is present
Because they are built on the smallest whole unit of matter…the atom…
Elements cannot be broken down into different simpler substances !!!!
What is the symbol that represents the element Carbon?
The capital letter ‘C’
What is the symbol that represents the element Helium?
The capital letter ‘H’ followed by a lowercase ‘e’
The symbol for an element will ALWAYS START WITH A CAPITAL letter
and…
it will have only ONE capital letter…(it may have a lower case letter).
Is this a model for an Element?
No…it’s got more than one type of atom
This is the compound - H2O
Compounds = two or more elements
that are chemically bonded together
Because the different types atoms are chemically bonded…
Compounds are NOT MIXTURES!
The properties of a compound are different than those of the element from with they are formed.
EX:
Hydrogen an explosive gas…Oxygen a clear gas that supports combustion.
H2O – clear liquid that puts out fire!
This model for has lines to help
show that the elements H and O are
chemically bonded together.
Think of these bonds as the energy
bonds required to hold the elements
together.
TWO OR MORE !
H2O H2O
NaCl
NaCl
C12H22O11
Can a compound be pure?
Sure…as long as only that compound is
present.
If it’s all H2O…it’s pure
Summary – Element vs. Compound
Elements are represented by SYMBOLS.
They always Start w/capital & have only one capital.
EX:
O = Oxygen
Fe = Iron
Because they are made from one type of atom…Elements cannot be broken down
into different simpler substances !!!!
Compounds are represented by FORMULAS
The formula is a recipe that shows what elements are chemically bonded
together in the compound.
EX: H2O = 2 Hydrogen bonded with 1 oxygen
CO2 = 1 Carbon bonded with 2 oxygen.
Because they are made from two or more types of atoms….compound can be broken into
simpler substances.
Which is an element?
Which is a compound?
A
A = Element
One type of atom
B
B = Compound
More than one
type of element
Which is pure?
A
B
Both
!
Are these containers pure?
B
A
NO !