BASIC
CHEMISTRY
ATOMS, ELEMENTS AND HOW THEY BEHAVE
IN THIS UNIVERSE…..
There is…….
•Matter – anything that has MASS
and takes up space.
•Space – what is not matter.
•Which is there more of????
WHERE DID MATTER COME FROM?
Big Bang
• Approx. 13 BYA
• Produced enormous amounts of energy!
• Energy eventually “chilled” (sort of) enough to
form basic building blocks of matter
• Evidence???
• Expanding Universe
• Red-shift
• Background radiation
BUILDING AN ATOM
Atoms = basic unit of matter
Made of…
• Electrons (e-)
• small, no mass, negatively charged
• Protons (p+)
• Has mass, positively charged
• Neutrons (n0)
• Has mass, no (neutral) charge
ATOM STRUCTURE
Protons and Neutrons
are located near the
center of the atom and
form the NUCLEUS
Electrons orbit around
the nucleus in specific
electron orbitals/shells.
Why are electrons attracted
to the nucleus?
What keeps the electrons
from “crashing in?”
STRUCTURE OF AN ATOM
e-
P+
Orbit
N
P+
N
e-
Nucleus
STRUCTURE OF AN ATOM
e
e
e
e
e
Orbit
e
N
P
Nucleus
P
N
e
e
e
e
e
Structure of an Atom
e
N
P
P
N
e
EACH
ORBIT IS A
SPECIFIC
DISTANCE
FROM THE
NUCLEUS.
KEY POINT!!!!
Atoms, can have DIFFERENT combinations of
electrons, neutrons and protons!
These different combinations makes the atoms
BEHAVE differently and have different
properties.
INTRODUCING THE ELEMENTS!
SO WHERE DID ALL THESE
DIFFERENT ATOMS COME FROM????
Telling the story of matter….
- Big Bang  HUGE amount of energy released
- Energy “chills” and starts to form basic building blocks
of matter
- First atoms form  Hydrogen and Helium.
- Hydrogen attracted to other hydrogen  Big balls of
hydrogen
- FUSION REACTION (aka stars)  smaller atoms fuse
together to form heavier elements (carbon, nitrogen,
phosphorus sulfur).
- SUPER FUSION  In supernovas even heavier elements
are formed.
WHERE THIS LEAVES US!
Approx 5 BYA…
- some leftover space debris (matter)
from star cycles start to coalesce in
different ways
- Hydrogen collected in center starts a
fusion reaction => our sun starts fusion
- Circling debris coalesces to form
planets, asteroid belt, moons, etc.
WHAT WE HAVE ON EARTH
Atoms can exist in varying forms on earth
- Compounds
- Two or more different atoms bonded together
- Ex. H20, CH4
- Elements
- substances consisting of only one type of
atom.
- A single atom is the smallest amount of an
element you can have.
- Ex. O2, H2
ATOMIC THEORIES AND DISCOVERIES
Dalton: Late 19th century
- thought the atom was nothing more than a tiny
indivisible sphere
Rutherford: Early 20th century
- Nucleus contains protons and neutrons
- Number of protons dictates which element it is.
- Electrons circle nucleus in orbits.
ATOMIC THEORIES AND DISCOVERIES (CONT.)
Neils Bohr
- Electron orbits
exist at only
certain energy
levels (distances)
from the
nucleus.
BOHR’S VIEW OF THE ATOM
Each orbit holds only a
certain number of
electrons
Orbit 1 – max 2
Orbit 2 – max 8
Orbit 3 - max 8
BOHR’S VIEW OF THE ATOM
Valence Electrons:
- Electrons in the outermost
orbit
- Determine how an atom
“behaves”
- atoms with not completely full
valences tend to interact
(bond) with other atoms.
BOHR’S VIEW OF THE ATOM
Elements with full “outer shells”
do not react
- Noble or “Inert” gases
- He, Ne, Ar, Kr, Xe, Rn
FULL VALENCE = NON REACTIVE
NOT FULL VALENCE = REACTIVE!
THE PERIODIC TABLE
Key Points for what the periodic table tells us.
Atomic number
= number of protons
Atomic Mass
=“approximate” number of protons + neutrons
If atom has a charge of zero, Electrons = Protons
HOW TO READ A PERIODIC TABLE
YOU TRY IT
Oxygen
Atomic # _______________
Atomic mass ____________
Number of
p+ ____________
n0 ____________
e- ____________
Sulfur
Atomic # _______________
Atomic mass ____________
Number of
p+ ____________
n0 ____________
e- ____________
IONS
When we say “atoms” we typically mean a
neutral charge
- number protons = number electrons
Sometimes and atom can gain or lose
electrons!
- now has a positive or negative charge =
ION!
ISOTOPES
Sometimes an atom of the SAME element
can gain or lose neutrons
- does it change the charge?
- does it change how it behaves?
Isotopes = atoms with the same number of
protons and electrons but different neutrons
COMPOUNDS
Two or more different types of atoms
bonded together in a set proportion. Ie.
CH4, H20, C6H12O6
MOLECULES
Contains more than one atom,
BUT can be the same type of
atom (O2, N2)
COMPOUNDS
Two or more different atoms bonded
together.
Type of bond depends on the number of
valence electrons of the atoms involved.
•Ionic
•Covalent
•Polar Covalent
Bonding Animations
TYPES OF BONDS
Ionic: one atom gives electrons to
another, creates opposite charges
IONIC BONDS OCCURS WHEN:
One element has only 1 or two valence electrons
and a complementary element has 7 or 6 valence
electrons
Elements bonding MUST have electrons that
equal “full shell number”.
Usually occurs between a metal (left side of
periodic table) and a non metal (right side of
periodic table)
TYPES OF BONDS
Covalent: atoms share electrons to get full
valences
COVALENT BONDS
Most often occur when one element
has 3-5 valence electrons.
TYPES OF REACTIONS
Metabolism – the sum of all chemical reactions in
living things
Anabolism – synthesis or building up
Catabolism – degradation or breaking down
Neutralization reactions
Occur between acids and bases
The products are often a salt and water
BONDING – DEPENDS ON VALENCE E-’S
Atoms will form bonds to get “full
valences”
Remember:
1st level holds 2 electrons
2nd level holds 8 electrons
3rd level holds 8 electrons
TYPES OF BONDS
Which do you think is stronger?
•Ionic: two atoms attracted by opposite
charges?
OR
•Covalent: two atoms holding on to
same electrons
IN LIVING SYSTEMS
We need covalent bonds to keep molecules together
(we don’t want them to dissolve in water)
Often, we consider covalent “stronger” in living
things. In reality, many ionic bonds require more
energy to break apart than covalent bonds.
So: in Bio, covalent are stronger than ionic (living
things), in Chem you are taught that ionic are
stronger than covalent (inorganic chem = non-living
things)
MIXTURES VS. COMPOUNDS
Mixtures have “ingredients” that do not
bind chemically with each other
•Each substance keeps its own property
•No definite proportions
•Types: solution, suspension, colloid
MIXTURE EXAMPLES
Solutions
Homogeneous
Consist of solvent (the dissolver) and solute (what is
being dissolved.
Water dissolves salt (water is the solvent)
Salt can dissolve in water (water is still the solvent)
Solutions consist of atoms, molecules and/or ions .
The particles are VERY small
MIXTURE EXAMPLES
Colloid
Particles which are larger than those in a solution,
but smaller than those in a suspension.
Will remain evenly distributed without settling (but
are generally cloudy)
Example: Milk
SOLUTIONS VS COLLOIDS
How are solutions and
colloids different?
Tyndall effect
Light cannot be seen “in”
a solution (it goes through)
Light is reflected (think fog)
and can be seen “in” the
colloid due to the reflection.
MIXTURES
Suspensions
Particles larger than colloids which can be
evenly distributed (by mixing) but will
eventually settle out.
Example: Oil and Water (but better
example is “solids in a liquid (like Italian
salad dressing)
OTHER “COOL
MIXTURES” OF MIXTURES
Emulsions
liquids in liquids (that usually don’t settle)
Mayonnaise
Gels
liquids “trapped” in a solid.
Gelatin (water and protein)
Aerosols
Solid or liquid particles in a gas
Smoke (solid in a gas)
Fog (liquid in a gas)
MIXTURES VS. COMPOUNDS
•Elements are Chemically bound
A compound has different properties than any
of the elements that make it upExample:
4 H2 (gas) + 2 O2 (gas)  2 H20 (liquid)
•Definite proportions required
• Ex. H20 means there are always two hydrogen
atoms per one oxygen atom
CHEMICAL FORMULAS
A chemical formula tells us three things:
•What elements are involved
•How many atoms of each you have
•How many molecules you have
CHEMICAL FORMULAS
•Ex: 3C6H12O6
•This means there are 3 molecules of
(C6H12O6) which is glucose
•1 molecule of (C6H12O6) contains 6 Carbon
atoms, 12 Hydrogen atoms and 6 Oxygen
atoms
•So how many H’s total are represented in
the formula at the top?
TYPES OF CHEMICAL REACTIONS
Synthesis Reactions
Two reactants combine to create a
“more complicated” product
A+BC
Which letter represents a product? Which
represents a reactant?
What is an example of a synthesis reaction?
DECOMPOSITION REACTION
A more complicated compound (larger
number of atoms) breaks down into 2
or more smaller (simpler)
components.
CA+B
enzyme
Protein  Amino acids
WHERE WOULD
DECOMPOSITION OCCUR?
In the digestive system!
Starches  simple sugars (mainly glucose)
Proteins  amino acids
Lipids  fatty acids
NEUTRALIZATION REACTIONS
Occur between an acid and a base.
After the reaction the products are
generally a salt (or ionic compound) and
water . (This is only if the reaction occurs in
an aqueous (water) environment.
Living things ALWAYS have an aqueous
environment!
WHERE WOULD NEUTRALIZATION
RXNS OCCUR IN YOU????
Intestines
The acidity of the stomach is very high
(this is to help break apart proteins). When
food leaves the stomach it needs to be brought
back to a pH of around 7-8
The pancreas produces sodium
bicarbonate, which will neutralize the acid and
adjust the pH to this level
WHERE WOULD NEUTRALIZATION
RXNS OCCUR IN YOU????
Blood
Your blood pH can vary depending on
waste products being carried to kidneys
from the cells.
Carbonic acid-bicarbonate ion acts as a
buffer to maintain pH at 7.4
REDOX REACTIONS
Concerned with the transfer of electrons!
Electrons carry energy!
Therefore bonds made by
electrons contain energy
Oxidation  Loss of electrons
Reduction Gain of electrons
WHERE DO REDOX
REACTIONS OCCUR?
Any place where you are transferring energy into a
compound, or releasing energy from a compound
Photosynthesis (light energy  chemical energy)
sunlight
CO2 + H2O  C6H12O6 + O2
Respiration (converts glucose ATP + CO2 and H2O
ENERGY, MATTER AND
CHEMICAL REACTIONS
Some reactions release energy
(exothermic). Product has LOWER energy
This means that the surroundings will
become warmer
Some reactions absorb energy (the
compound created has more energy that
what it started with (endothermic)
This means the surroundings will cool
REACTIONS
REACTIONS
WHAT IS THE SOLVENT FOR
THE “BODY”
WATER!
What does this mean?
THE ANSWERS
All reactions in the body take
place in water!
Cells contain water, cells are
surrounded by water
Hmm…Why aren’t we “wet”?
THE MOST IMPORTANT
INORGANIC MOLECULE OF LIFE
WATER!
INORGANIC
Any molecule containing C and H (hydrocarbons) is
ORGANIC
Any molecule that is ORGANIC in a living thing
contains Carbon, Hydrogen, and Oxygen (we don’t
have CH “only” molecules)
Any other molecule, is inorganic.
Examples: H2O, CO2, NaCl
WHY IS WATER IMPORTANT
- What are the “jobs” that water has
It is a solvent – dissolves things
It cushions – think of a water bed, or a gym
mat
It lubricates – think of a slip and slide
It transports – think blood
It is a medium – this means it is a place where
reactions can take place
Maintains temperature – think homeostasis
These are not properties, these are not
characteristics…these are “FUNCTIONS or JOBS”
-
WATER- POLAR COVALENT MOLECULE
•Share electrons but not equally
• slight (-) charge in the O
• slight (+) charge in the H’s of
water
BECAUSE WATER IS POLAR
PROPERTIES (CHARACTERISTICS) OF WATER
1. It is cohesive
2. It is adhesive
3. It has surface tension
4. It demonstrates capillary action
5. It is a universal solvent
6. It has high specific heat
PROPERTIES OF WATER
Polarity of Water movie
PROPERTIES OF WATER
Cohesion
•Water molecules stick
to other water molecules
•Creates a high surface
tension
•Belly flop anyone?
Properties of Water
Adhesion
•Water molecules stick to other
substances with partial
charge
•Adhesion creates
surface tension
Properties of Water
CAPILLARY ACTION
The movement of water within the spaces
of a porous material due to adhesion,
cohesion and surface tension
The smaller the diameter of
the glass tube, the more the
water will climb.
The attraction to the glass
is stronger than the
attraction of water molecules
to each other.
PROPERTIES OF WATER
 Universal Solvent
 Polarity of water allows it to
interact with neighboring polar or
ionic molecules
 Dissolves or suspends more
substances than any other
solvent
 What will not dissolve in water?
PROPERTIES OF WATER
Universal Solvent – making salt water
PROPERTIES OF WATER
EXAMPLE NaCl + H2O  Na+ + Cl- + H2O
 Oxygen end surrounds sodium ion
 Hydrogen side surrounds chloride
 sodium & chloride separate as ionic
bonds are broken
 Is this a solution, suspension or
colloid?
pH
What does pH measure (I mean REALLY..what
ion is it measuring)
It is measuring the amount of “extra”
hydrogen ions in water!
pH scale
Simply tells us the relative concentration of
hydrogen atoms
•Ranges from 0 -14
•Acidic range
• 0-6.3
6.3 is almost neutral
•Basic
• 7.8 -14
7.8 is almost neutral
Your body must maintain itself between
WHAT IS THE PH RANGE
OF MOST FOODS?
Fruits and Vegetables
pH
Meat – live flesh has a
pH of 7.1
steak (animal is dead)
2-6
pH of 5.7 – 6.2
As meat begins to decompose, the pH gets higher (ammonia
is being formed from the breakdown of proteins).
http://www.foodsafety.wisc.edu/business_food/files/Approximate_pH.pdf
PH OF MOST
CLEANERS
Chlorine Bleach – whitens/stain removal – 11-13
Dirt/grease/grime
Ammonia –
pH 11 -12
Oven Cleaner –
pH
Tub and Tile Cleaner
11-13
11-13
Borax – oils and organic dirt –
10
Baking soda – gentler basic cleaner
8-9
OTHER CLEANERS
Dish detergent (liquid) – 7-8
To get rid of “mineral deposits
Vinegar –(cleaning) 2-3
Toilet bowl cleaner – 1-3
Lemon juice – 2 (copper cleaner too)
Digestive Tract pH
Saliva
6.5 - 7.5
Stomach (upper)
4.0 - 6.5
(lower)
1.5 – 4.0
secretes (HCI) and pepsin (an enzyme)
Small intestine
(nutrients absorbed)
7.0 - 8.5.
Colon – waste
4.0 - 7.0.
URINE
pH 6.5- 7.0 (healthy, morning)
pH 7-8 (healthy afternoon)
higher pH due to buffering of
“acid” foods
HOW IS PH
“CONTROLLED?
Buffers!
WHAT IS A BUFFER
A molecule that can either be a weak acid
or a weak base
It can interact with strong acids and bases
to bring the pH “back to normal”
http://www.mhhe.com/physsci/chemistry/essentialchemistry/f
lash/buffer12.swf
Cells work  produces H+  acidic blood
H2CO3 + H+  H2O + CO2 (exhale)
EXCESS H+
Equilibrium is shifted to the left. This means that some
of the added hydrogen ions will react with the
bicarbonate ions to produce carbonic acid and the
carbonic acid will dissociate into carbon dioxide and
water as shown below.
TOO FEW H+
Now, the equilibrium will shift to the right.
More carbon dioxide will combine with water
and more carbonic acid will be produced and
more hydrogen ions and bicarbonate ions will be
produced.
CHEM IS IMPORTANT IN BIO
The smallest unit of matter is an atoms, which make up
compounds and ions (and even isotopes)
Living things are made of matter and energy
Living things transfer matter and energy in and out of
themselves
Matter in living things can be ions, covalent compounds, ionic
compounds. Matter can be solid, liquid or gas, and can be in
solution, suspension, or even found as a colloid
Water is the solvent in all living things
The ability of matter to dissolve in water is often dependent
on temperature and pH