Transcript Biochemistry PowerPoint (part 1)

Here is some helpful information:
PROTON, NEUTRON and ELECTRON HANDOUT:
1. Atomic Number= # of Protons
2. # of Protons= # of Electrons
3. Atomic Mass= Protons + Neutrons
(Atomic Mass and Atomic Weight are the same thing)
Elements
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Element= a pure substance that is made up of 1 type of
atom.
Elements are represented by a symbol (1 or 2 letters).
– C stands for carbon.
– Na stands for sodium
Periodic Table= arranges elements according to the # of
protons an atom has.
Atoms
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Atoms are made of subatomic
particles:
Protons (P) (+ charge)
Neutrons (N) (No charge)
Electrons (e-) (- charge)
The protons and neutrons are
bound together in the dense
nucleus.
Electrons move in the space
around the nucleus.
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Atoms
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NUCLEUS= center of the atom.
Determines the weight of the atom.
(# of protons + # neutrons)
PROTONS:
Positive charge (+1) mass =1 (amu)
atomic #= # of protons in an atom.
Adding or removing protons from the
nucleus of an atom creates a different
element.
NEUTRONS:
No charge
mass=1 (amu)
# of neutrons is determined by
comparing the atomic number to the
atomic mass.
Atoms
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ELECTRONS: Negative
charge= -1
Move in orbits (shells)
Each orbit has a maximum #
of e- it can hold:
1st shell: 2 e2nd shell: 8 e3rd shell: 8 eAtoms are NEUTRAL because
the subatomic particles have
equal but opposite charges.
# of protons = # electrons
Atoms
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Krypton's atomic number= 36
Krypton has 36 protons in its nucleus.
Atoms
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Atomic Mass #= (# of Protons) + (# of
Neutrons)
84 = (# of Protons) + (# of Neutrons)
84 = 36 + (#of Neutrons)
48= #of Neutrons
Isotopes
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Isotopes: different forms of the same element.
They have the same:
- Atomic #
-# of Protons
- # of Electrons
They have different # of Neutrons
Ex. Carbon-12 (6 neutrons),
Carbon-13 (7 neutrons),
& Carbon-14 (8 neutrons)
Isotopes and Radioactivity
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Some of the larger elements have isotopes that are
unstable.
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They slowly change into a more stable form by releasing
neutrons. This process releases radioactive particles
and energy too.
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These isotopes are considered radioactive.
Isotopes and Radioactivity
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Radioactive isotopes have many functions in
science:
• 1) “markers.”
• 2) medical procedures.
• 3) treatment (Cancer patients receive radiation
to kill the cancer cells.)
•
Long-term exposure or exposure to high-energy
radiation can cause diseases such as cancer.
Atoms
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ELECTRONS: Negative
charge= -1
Move in orbits (shells)
Each orbit has a maximum #
of e- it can hold:
1st shell: 2 e2nd shell: 8 e3rd shell: 8 eAtoms are NEUTRAL because
the subatomic particles have
equal but opposite charges.
# of protons = # electrons
Am I “happy”
Valence e
Each orbit has a maximum # of
e- it can hold:
1st shell: 2 e2nd shell: 8 e-
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Outer e-= Valence eTo be “happy” atoms want to
fill up their outer shell.
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– Share e– Add/lose e-
OCTECT RULE- They want 8 e- in outer shell
OCTECT RULE- They want 8 e- in outer shell
CARBON
Hydrogen
Chlorine
Phosphorous
Compounds & Bonding
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Compounds= Chemical combination of 2 or more elements.
The atoms in compounds are held together by chemical
bonds:
– Ionic & Covalent Bonds
Ionic bonds = transfer electrons
– The transfer of electrons creates charged atoms called ions.
Atoms
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When an atom loses an electron it will have more protons
than electrons = positive charge (CATION):
Li +,
Na +,
Mg 2+ , Ca 2+
Ion
Cat
Video!!
(usually metals)
Cation
and
Anion
When an
atom gains
an electron
it will have more
electrons
than protons=
negative charge (ANION):
Practice
Worksheet!!
Cl - ,
Br - ,
IS 2(usually nonmetals)
Compounds & Bonding
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Covalent bonds= share electrons
– Compounds with covalent bonds are molecules.
– There can be single, double, or triple bonds depending
on the # of electrons shared
Covalent Bonds
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NonPolar Covalent Bonding= equal sharing of ePolar Covalent Bond= If one atom in the bond attracts e- more
than
the other
atom.Story Video
H2O
Love
– UNEQUAL SHARING OF e(part 1)
Electron rich side= slightly negative end
Electron deficient side = slightly positive
2-2 Water Molecule
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Water molecule (H2O) is a neutral molecule.
Protons: (H) 1+ (H) 1 + (O) 8 = (H2O) 10 protons
E-: (H) 1 + (H) 1 + (O) 8 = (H2O) 10 electrons
Polarity
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What has a stronger pull for electrons, the
H or the O?
There is a greater probability of finding the shared
electrons near the O than near the H.
Polar covalent bond = unequal sharing of electrons.
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What will the partial charges be on
the O & H?
Oxygen= Slightly Negative
Hydrogen= Slightly Positive
8P
8N
1P
0N
1P
0N
Hydrogen Bonds
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POLARITY
Because of the partial (+) and partial (-), polar molecules can
attract each other.
Hydrogen Bonding= The attractive force between one
water molecule and another.
(MUST involve a Hydrogen atom)
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The H in one water molecule is attracted to the O in another
Water molecule.
Hydrogen Bonds
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A single water molecule can be involved in 4 hydrogen
bonds.
Multiple hydrogen bonding is responsible for water’s
properties:
Cohesion, Surface Tension and Adhesion.
Water- Cohesion
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Cohesion = waters attraction to other water molecules
because of polar properties
– Surface tension = allow objects that are more dense than
the liquid to be supported on the surface of the liquid
without sinking.
– Ex. insects walking on a ponds surface.
Water- Adhesion
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Adhesion = water attracted to other materials.
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Ex: Water in a straw, water moves through trees this way
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Water is attracted to other material and then cohesion
holds the water together as it rises.
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A water molecule can react to
form ions.
H2O OH- + H+
The pH Scale- indicates the
[H+] ions in a solution.
The pH Scale ranges from 0-14
A pH of 7= [H+] = [OH-]
(neutral) Pure water
Solutions with a pH below 7 is
ACIDIC because they have
more H+ ions.
Solutions with a pH above 7 is
BASIC because they have more
OH- (hydroxide) ions.
pH Scale
pH Scale
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Low pH=
Acidic
High pH=
Basic
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Acids= compounds that
form/release H+ ions in
solution.
Contain a higher [H+] ions
than pure water.
pH values below 7.
Strong acids have a pH range
from 1-3.
Example: hydrochloric acid
(HCl) dissolves in water as
follows:
HCl (H2O) H+ + Cl-
pH Scale
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Bases= compounds that
form/release OH- ions in
solution.
Also known as ALKALINE
Contain a lower [H+] ions than
pure water.
pH values above 7.
Strong bases have a pH range
from 11-14.
Example: sodium hydroxide
(NaOH) dissolves in water as
follows:
NaOH H2O Na+ + OH-
pH Scale
pH Scale
It will depend
on the number
of molecules
that break apart
when the acid or
base dissolves in
water.
If ALL the
molecules of an
Acid break apart
and release H+=
STRONG
If only a few
molecules of an Acid
break apart and
release H+= Weak
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The pH of most cells in the human must
be kept between 6.5 - 7.5.
Controlling the pH is important for
maintaining the homeostasis
BUFFERS– weak acids or bases that can
react with strong acids or bases to
prevent sudden changes in pH.
pH Scale
1) bicarbonate buffer system
2) phosphate buffer system
3) protein buffer system
*If they find themselves in a solution with a lot of H+ floating around (an
acid), they act as bases and suck up the excess H+
*And if they find themselves in a solution lacking free H+ (a base), they
donate their H+ to the solution.
Solutions and Suspensions
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Mixture-a material composed of two or more elements or
compounds that are physically mixed together, but not
chemically combined.
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2 Types of Mixtures that are made with water:
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Solutions and Suspensions
Solutions
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Solution= a mixture of two or more substances in which the
molecules of the substance are evenly distributed. (particles
dissolve)
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Example: Salt Water
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solute-the substance that is dissolved: Table Salt
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solvent-the substance in which the solute dissolves: Water
Cl-
ClNa+
Na+
Water
Water
Suspensions
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Suspensions- When materials do not dissolve when placed in
water but break into pieces that do not settle out.
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Particles in suspensions are larger than particles in a solution.
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Particles are suspended (they will NOT dissolve).
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Example: Blood, Italian Dressing, Oil and Water & Sand in water.
ALIEN JUICE BAR:
Testing your Acid and Base Knowledge
Periods and Groups
• Periods go from left to
right
• Groups go up and
down
Bohr Models RULE
• Show just electrons with
energy levels
• 1st level holds 2 e• 2nd level holds 8 e• 3rd level holds 18 but is
stable at 8 e• 2-8-8 RULE!!
• Must fill an energy level
to capacity before
moving to the next
energy level
Bohr Models
Lewis Dot Structure
• Show Valence e- ONLY!!
• top-bottom-left right and then begin to pair e-.