What are these lists
of?
They are the
ingredients to
shampoo
(above) and a
meal bar (right)
What are these ingredients?
• Are these even real things?
• Where did they come from?
Elements, Compounds, and
Molecules
• We have only 26
letters in our
alphabet.
• But we can combine
these 26 simple
letters in a variety of
ways to form tens of
thousands different
English words.
• The periodic table
of elements has
118 different
“letters”
• We can combine
these elements to
form millions of
different
substances.
• Including these
substances:
Atoms can combine
• Two or more atoms can chemically combine
by sharing, taking away, or giving away
electrons
Oxygen O2
Water H2O
Salt NaCl
Molecule
• When the atoms combine, they form a
molecule.
• A molecule is made of two or more atoms
which have chemically combined.
• Molecules might be made of atoms of the
same element.
• Or molecules might be made of two or more
atoms of different elements
• We call these compounds.
• Compounds are molecules made of two or
more different elements
Is it a molecule? Is it a compound?
Is it both?
Molecule!
Molecule
and a
compound!
Molecule!
https://www.youtube.com/watch?v=gS3kmdp4t_0
Molecules and compounds review. All elements are at least 21 years old in this
video.
Review:
• Are all of these substances molecules?
• Yes! They all have two or more atoms chemically
combined.
• Are all of these substances compounds?
• No- only the bottom row has two or more atoms of
different elements, which make them compounds
Molecules can come in many shapes
and sizes!
Nylon- used in many plastics
Largest molecule ever made by
humans!
http://www.popsci.com/science/article
/2011-01/most-massive-syntheticmolecule-could-be-used-deliver-drugsor-make-new-materials
We are made of molecules!
• DNA is made up of
molecules called
nucleotides.
• Each nucleotide
contains a phosphate
group, a sugar group
and a nitrogen base.
• The four types of
nitrogen bases are
adenine (A), thymine
(T), guanine (G) and
cytosine (C).
Our DNA molecules are so large, they have to coil
up in our chromosomes, which are found in the
nucleus of every cell
Anti-social atoms
• Some atoms don’t like to chemically combine,
or bond, with other atoms.
• This special group is called the Noble Gases
and they are all found in the last column of
the periodic table.
How can I tell what is in a molecule?
A formula unit will tell us:
1. What elements are in a
molecule.
2. How many atoms of each
element are in a molecule.
NaCl- a molecule of salt
• Na- Sodium
• Cl-Chlorine
• A molecule of salt is made
of one atom of sodium and
one atom of chlorine.
H2O – a molecule of water
•
•
•
•
H- Hydrogen
O- Oxygen
What does the 2 mean?
The number tells us how many
atoms of the element there are.
• The number is put after the
element it is referring to as a
subscript (low) number.
• There are 2 Hydrogen atoms,
and one oxygen atom in a
molecule of water.
Can you tell what elements and how
many are in this compound?
• Salt- 1 Sodium atom and 1 Chlorine atom
• Glucose- 12 Carbon, 22 hydrogen, 11 oxygen
atoms
• Vinegar- 2 carbon, 3 hydrogen, 2 oxygen atoms
• Baking Soda- 1 sodium, 1 hydrogen, 1 carbon, 3
oxygen atoms
What elements? How many atoms?
Mixtures
• Mixtures occur when
the atoms or
molecules mix
together, but do not
chemically combine
or bond.
• Examples include:
air, salt water,
lemonade, salad
dressing
The cruelest mixture EVER!
Mixture!
Element
Compound
Mixture!
Element!
Compound!
Match the picture to the category