MKusanagi
10-17-2007, 09:30 PM
I've found that taking notes doesn't help... unless you actually use them. So let's do that. I'm going to post notes I have taken. And you should do. And together we will help eachother and possibly learn something.
My Chemistry Notes:
Ch2
- Stratospheric ozone plays a vital role in protecting earth's surface from solar radiation
- 1970's: discovered that human-produced chemicals destroy ozone
- policies were put in place and situation improved
- Antarctica has it the worst
- Ozone found in troposphere and stratosphere
Ozone Equation
energy + 3O2---> 2O3
Energy must be absorbed for ^ to happen otherwise it will remain O2
Allotropes: 2 or more forms of same element, differ in molecular or crystal structure & therefore in properties.
Ozone layer is 20-30 km up
Ozone filters out UV radiation
Ozone layer: region of maximum O3(ozone) concentration
Atomic number is the # of atoms
Periodicity of properties is chiefly the consequence of the number and distribution of electrons in the atoms of the elements
Outer (valence) electrons- particularly important because they account for many of the chemical and physical properties of the corresponding elements.
Electrons are arranged in levels around the nucleus
The innermost level houses electrons that are strongly attracted to +-charged nucleus
Valence electrons indicated in periodic table by number heading column of element.
Atoms also contain neutrons
Isotopes: two or more forms of the same element (same number of protons) whose atoms differ in number of neutrons, and hence in mass
-isotopes are identified by mass number: sum of the number of protons and neutrons in the atom
mass number is given in periodic table
-example of isotope: deuterium is a form of hydrogen but unlike hydrogen which has no neutron (hence the mass number of approx 1 since a proton weighs 1) it does and therefore its mass number is around 2.
hydrogen can be called H-1 since its mass number is 1 (not because its the first)
deuterium because of its mass can be called H-2
Another isotope of hydrogen is tritium has 2 neutrons in addition to the 1 proton. Therefore it is H-3
MOLECULAR STRUCTURE
covalent bond is where electrons between two interacting atoms are shared.
single bond is a covalent bond that shares 1 pair of electrons
double bond is where 2 pairs are shared
triple bond....3 pairs
sometimes there are bonds that are in between single and double. resonance form: reality of molecular structure does not always correspond with Lewis Structure
octet rule: fact that electrons in many molecules are arranged so that every atom (except hydrogen) shares in eight electrons
*going over Lewis Structure method or dot structure*
Polyatomic molecules: compounds that contain molecules with more than 2 atoms.
Waves of Light
wavelength: distance between successive peaks
frequency of waves passing a fixed point in one second
nanometer: (nm) 1/1,000,000,000 of a meter or 1*10^(-9)
shorter wavelength=higher frequency and longer=lower
units per 1/s or s^(-1) <--- AKA hertz (Hz)
Frequency= speed of light/wavelength or 3.00*10^8/wavelength
Electromagnetic spectrum ranges from very low energy radio waves to high energy X-ray or gamma-ray
radiant energy is term used to refer to entire collection of different wavelengths, each with its own energy
Earth receives radiant energy from sun
-although each type of radiation has a different wavelength and frequency the speed they all travel is same: 3.00*10^8
QUANTUM THEORY
energy distribution is not continuous. it consists of many steps. this energy distribution is called QUANTIZED.
Analogy: quantized energy is like steps on staircase, not like a ramp where any sized stride is allowed.
photons: individual bundles of energy
-einstein felt radiation should be viewed as constituted of photons.
-okay, so photons are considered elementary particles
-elementary particles are particles that don't have a substructure.
-basically, there are no smaller components of them. here, my friends is some amazing science.
These photons have no mass, however. my god, i want to know more. how can it not have mass if it is a particle? if its a thing that is no just pure energy than it surely has to have mass.
Wave-particle duality- can have wave-like properties and particle-like properties
The energy of a single photon(E) is directly proportionate to the frequency(v) and inversely proportionate to the wavelength(K). as wavelength gets shorter, energy increases. so...
E=hv=hc/K
h=planck constant (6.63*10^(-34) Joule*Second
Joule is a unit of energy
c=speed of light or 3.00*10^8
I will be taking more notes. I encourage you to participate. So I don't feel awkward.
My Chemistry Notes:
Ch2
- Stratospheric ozone plays a vital role in protecting earth's surface from solar radiation
- 1970's: discovered that human-produced chemicals destroy ozone
- policies were put in place and situation improved
- Antarctica has it the worst
- Ozone found in troposphere and stratosphere
Ozone Equation
energy + 3O2---> 2O3
Energy must be absorbed for ^ to happen otherwise it will remain O2
Allotropes: 2 or more forms of same element, differ in molecular or crystal structure & therefore in properties.
Ozone layer is 20-30 km up
Ozone filters out UV radiation
Ozone layer: region of maximum O3(ozone) concentration
Atomic number is the # of atoms
Periodicity of properties is chiefly the consequence of the number and distribution of electrons in the atoms of the elements
Outer (valence) electrons- particularly important because they account for many of the chemical and physical properties of the corresponding elements.
Electrons are arranged in levels around the nucleus
The innermost level houses electrons that are strongly attracted to +-charged nucleus
Valence electrons indicated in periodic table by number heading column of element.
Atoms also contain neutrons
Isotopes: two or more forms of the same element (same number of protons) whose atoms differ in number of neutrons, and hence in mass
-isotopes are identified by mass number: sum of the number of protons and neutrons in the atom
mass number is given in periodic table
-example of isotope: deuterium is a form of hydrogen but unlike hydrogen which has no neutron (hence the mass number of approx 1 since a proton weighs 1) it does and therefore its mass number is around 2.
hydrogen can be called H-1 since its mass number is 1 (not because its the first)
deuterium because of its mass can be called H-2
Another isotope of hydrogen is tritium has 2 neutrons in addition to the 1 proton. Therefore it is H-3
MOLECULAR STRUCTURE
covalent bond is where electrons between two interacting atoms are shared.
single bond is a covalent bond that shares 1 pair of electrons
double bond is where 2 pairs are shared
triple bond....3 pairs
sometimes there are bonds that are in between single and double. resonance form: reality of molecular structure does not always correspond with Lewis Structure
octet rule: fact that electrons in many molecules are arranged so that every atom (except hydrogen) shares in eight electrons
*going over Lewis Structure method or dot structure*
Polyatomic molecules: compounds that contain molecules with more than 2 atoms.
Waves of Light
wavelength: distance between successive peaks
frequency of waves passing a fixed point in one second
nanometer: (nm) 1/1,000,000,000 of a meter or 1*10^(-9)
shorter wavelength=higher frequency and longer=lower
units per 1/s or s^(-1) <--- AKA hertz (Hz)
Frequency= speed of light/wavelength or 3.00*10^8/wavelength
Electromagnetic spectrum ranges from very low energy radio waves to high energy X-ray or gamma-ray
radiant energy is term used to refer to entire collection of different wavelengths, each with its own energy
Earth receives radiant energy from sun
-although each type of radiation has a different wavelength and frequency the speed they all travel is same: 3.00*10^8
QUANTUM THEORY
energy distribution is not continuous. it consists of many steps. this energy distribution is called QUANTIZED.
Analogy: quantized energy is like steps on staircase, not like a ramp where any sized stride is allowed.
photons: individual bundles of energy
-einstein felt radiation should be viewed as constituted of photons.
-okay, so photons are considered elementary particles
-elementary particles are particles that don't have a substructure.
-basically, there are no smaller components of them. here, my friends is some amazing science.
These photons have no mass, however. my god, i want to know more. how can it not have mass if it is a particle? if its a thing that is no just pure energy than it surely has to have mass.
Wave-particle duality- can have wave-like properties and particle-like properties
The energy of a single photon(E) is directly proportionate to the frequency(v) and inversely proportionate to the wavelength(K). as wavelength gets shorter, energy increases. so...
E=hv=hc/K
h=planck constant (6.63*10^(-34) Joule*Second
Joule is a unit of energy
c=speed of light or 3.00*10^8
I will be taking more notes. I encourage you to participate. So I don't feel awkward.