Transcript Ch. 2 Chemical Basis of the Body (pp. 26-33)

Ch. 2 Chemical Basis of the Body (pp. 26-33)
Matter
*Basic material of
universe
*Anything which
occupies space and
has mass
*Mass and weight
are different
*Mass is the amount of
matter something has
*Weight is the effect of
gravity on something
*EX. On the moon your
mass would be the
same as it is here on
Earth but your weight
would be different
(lighter).
3 Forms of Matter
Solid
Liquid
Gas
Solid
Tightly
linked
Definite
shape
Vibrate in
place
Liquid
Not so tight
Maintains fix
volume
Fits container
Gas
Loose
Fits
container
Move
rapidly
Atoms
*Smallest units of
matter that have
their own distinct
properties
*Based on these
properties, they are
classified into
elements
*109 elements, 92
occur naturally
Elements
Body has about 3536 elements in it.
However, C, H, O
and N make up 96%
of body mass. Add
Ca and P and this
makes up 99% of
body mass. The rest
are in small
numbers.
O = 65%
N = 3%
C = 18%
H = 10%
Ca = 1.5%
P = 1.0%
Atomic Structure
*Nucleus and electron shell
*Nucleus contains protons (+)
and neutrons (o). These
have about the same mass
and make up most of the
atom’s mass.
*Electron shells (electron
orbitals or energy levels)
contain electrons (-) which
are 1/1800 the mass of a
proton. They travel at the
speed of light (186,000
m/p/s).
Sub Atomic Particles
Protons are
positively
charged
Neutrons are
neutral, no
charge
Sub Atomic Particles
Electrons are
negatively
charged
Sub Atomic Particles
*If the number of
protons is the same as
the number of electrons
in an element then
there is no electric
charge
*When atoms gain or
lose electrons they take
on an electric charge
and become ions.
Atomic number is
the number of
protons, which is the
same as the number
of electrons in a
stable element
Atomic mass is the
number of protons
and number of
neutrons together
Sub Atomic Particles
http://science.widener.edu/svb/tutorial/
protons.html
Molecules
*Two or more similar atoms
combined
*Diatomic molecules are “7 to
9 down to iodine, hydrogen
doesn’t rhyme”
*When atoms are different,
they form a molecule called
a compound. EX. Na + Cl 
NaCl
*They have their own
properties which are
different than the properties
of the individual atoms
Chemical Bonds
*When electrons are
gained, shared or lost
*Invisible force which
holds 2 atoms together
Chemical Bonds
*Electron shell (2,8,8,etc)
or energy level is lowest
near nucleus and higher
as you come out
* The outer shell shows
how stable an atom is
* If it is full, it is inert
and will not react (most
stable form). Look at
VIII all inert gases
*If it is not full, it is
reactive and will react
to become more stable.
QUSTIONS 1-22
?
3 Main Types of Chemical Bonds
1. Ionic
*Transfer of electrons
2. Covalent
*Sharing of electrons
3. Hydrogen bonds
*Only formed among hydrogen atoms
1.Ionic bonds
*Electrostatic charge due to
opposite charges
*Weak charges
*EX. NaCl
*Drop NaCl in water and it
ionizes and forms Na+1 and
Cl-1
*Na+ is known as a cation
and Cl- is known as an anion.
Both are important in the
body.
*Look at bond. Na atomic
number is 11 and Cl atomic
number is 17
2. Covalent bonds
Sharing of
electrons
Stronger bonds
EX. H2O. Look at
bond. H atomic
number is 1 and
oxygen atomic
number is 8.
* H20 2 single
covalent bonds
H-O-H
*H2 A single
covalent bond
H-H
*O2 Double
covalent bond
O=O
Covalent bonds
3. Hydrogen bonds
*Very weak
*Formed between
hydrogen atoms and
a molecule with a
weak negative
charge
*Attractive force is
electrostatic
Chemical Reactions
*Atoms and
molecules
react
*Bonds
broken and
formed
*New product
produced
2 types
1. Synthesis
2. Decomposition
1. Synthesis
*Bonds formed
*Known as anabolism
*Combine atoms, ions,
molecules to form larger
molecules. Na + Cl 
NaCl. The Na and Cl are
reactants and the NaCl
is the product.
*A + B  AB
2. Decomposition Reactions
*Bonds broken
*Known as
catabolism
*Break down of
molecules into
simpler molecules,
atoms and ions.
AB  A + B
QUSTIONS 23-46
?
Health clinic: Clinical use of
atomic particles
* Isotopes are same
atoms but have
different number of
neutrons
*EX. Hydrogen usually
has 1 proton and 0
neutrons. This is what
water is made from.
However, when
hydrogen has 1 proton
and 1 neutron, it is an
isotope called
deuterium or heavy
water.
*Some isotopes are
stable and have similar
properties like their
common atom.
*Some isotopes have
unstable nuclei
*Lose neutrons or
protons at measurable
rates
*These are called
radioisotopes
Radioisotopes
*By losing subatomic
particles, energy is
released called
radioactive decay.
*This energy can
penetrate and destroy
tissues
*Since rapidly dividing
cells are more sensitive
to destructive effects of
radiation, this is why
radiation is good on
cancer.
X-Rays
*Also use radiation
*Loss of energy when
electrons move from
higher electron shell to
lower shell
*X-rays pass through
soft tissue but not bone
*Good on teeth and
bone
*Mammogram: Since
tumor is more dense
than soft tissue, x-rays
are good.
QUESTIONS 23-59
?