Atomic Number
-Atomic number=number of protons
atomic mass - atomic number = number of neutrons
Isotopes
-Same atomic number but different mass
For example there are 3 types of hydrogen atoms
1H 2H 3H
-Not all atoms of the same element are identical
Mass Spectrometers
-Are used to determine the abundance and mass of the isotopes of elements
-A device known as a mass spectrometer can be used to determine the relative abundance and the mass of the isotopes in an element
-Isotopes are elements that have the same atomic number(same element) but different atomic masses
Helpful links
Isotopes and atoms
http://www.chem4kids.com/files/atom_isotopes.html
http://www.daviddarling.info/encyclopedia/I/isotope.html
Mass spectrometer
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/maspec.html
Wednesday, October 27, 2010
Monday, October 25, 2010
Quantum Mechanics
Bohr's Theory
The electron is a particle that must be in orbital in the atom.
Quantum Theory
- The electron is like a cloud of negative energy or a wave.
- Orbitals are areas in 3D space where the electrons most probably are.
- The energy of the electron is in its vibration modes like notes on a guitar string.
- Photons are produced when high energy modes can change to lower energy modes.
S Orbitals
- Each orbital holds 2 electrons.
P Orbitals
- There are 3 suborbital
- Each contains 2 electrons
- Total of 6 electrons.
D Orbitals
- There are 5 suborbitals
- Each contains 2 electrons
- Total of 10 electrons
F Orbitals
- There are 7 suborbital
- Each contains 2 electrons
- Total of 14 electrons
To figure out what and how many electrons there are in one element while using this method we would have to look at this chart : http://www.google.ca/imgres?imgurl=http://www.mpcfaculty.net/mark_bishop/periodic_table_blocks_alone.jpg&imgrefurl=http://www.mpcfaculty.net/mark_bishop/complete_electron_configuration_help.htm&usg=__bLyOjtz-Gs86FIFcYq257xkeOzw=&h=348&w=607&sz=60&hl=en&start=0&sig2=jrC7eVhaOYmzHVETriUkqA&zoom=1&tbnid=5igjc12lXF7FoM:&tbnh=116&tbnw=203&ei=62HGTN-eJIn4swPTvaWODQ&prev=/images%3Fq%3Dperiodic%2Btable%2Borbitals%26um%3D1%26hl%3Den%26biw%3D842%26bih%3D935%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=219&oei=62HGTN-eJIn4swPTvaWODQ&esq=1&page=1&ndsp=15&ved=1t:429,r:3,s:0&tx=111&ty=30
To see how many electrons and what type of electrons there are in a single element you would have to look at the chart.
For example, to find Magnesium(12) you would have to start off at Hydrogen which will start off as 1s^2.
To get 1s^2 you would have to look at the chart and see how many 1s are there, there are 2 so you would have to square it, and you keep on doing that until you stop until Magnesium.
So then your final answer would be, 1s^2 2s^2 2p^6 3s^2
It stops at 3s^2 because that's where Magnesium is. But if it would stop at Sodium which is one before Magnesium. Your answer would be almost the same, but instead it would look like this, : 1s^2 2s^2 2p^6 3s
-A Meldrick Mendoza productions : )
The electron is a particle that must be in orbital in the atom.
Quantum Theory
- The electron is like a cloud of negative energy or a wave.
- Orbitals are areas in 3D space where the electrons most probably are.
- The energy of the electron is in its vibration modes like notes on a guitar string.
- Photons are produced when high energy modes can change to lower energy modes.
S Orbitals
- Each orbital holds 2 electrons.
P Orbitals
- There are 3 suborbital
- Each contains 2 electrons
- Total of 6 electrons.
D Orbitals
- There are 5 suborbitals
- Each contains 2 electrons
- Total of 10 electrons
F Orbitals
- There are 7 suborbital
- Each contains 2 electrons
- Total of 14 electrons
To figure out what and how many electrons there are in one element while using this method we would have to look at this chart : http://www.google.ca/imgres?imgurl=http://www.mpcfaculty.net/mark_bishop/periodic_table_blocks_alone.jpg&imgrefurl=http://www.mpcfaculty.net/mark_bishop/complete_electron_configuration_help.htm&usg=__bLyOjtz-Gs86FIFcYq257xkeOzw=&h=348&w=607&sz=60&hl=en&start=0&sig2=jrC7eVhaOYmzHVETriUkqA&zoom=1&tbnid=5igjc12lXF7FoM:&tbnh=116&tbnw=203&ei=62HGTN-eJIn4swPTvaWODQ&prev=/images%3Fq%3Dperiodic%2Btable%2Borbitals%26um%3D1%26hl%3Den%26biw%3D842%26bih%3D935%26tbs%3Disch:1&um=1&itbs=1&iact=rc&dur=219&oei=62HGTN-eJIn4swPTvaWODQ&esq=1&page=1&ndsp=15&ved=1t:429,r:3,s:0&tx=111&ty=30
To see how many electrons and what type of electrons there are in a single element you would have to look at the chart.
For example, to find Magnesium(12) you would have to start off at Hydrogen which will start off as 1s^2.
To get 1s^2 you would have to look at the chart and see how many 1s are there, there are 2 so you would have to square it, and you keep on doing that until you stop until Magnesium.
So then your final answer would be, 1s^2 2s^2 2p^6 3s^2
It stops at 3s^2 because that's where Magnesium is. But if it would stop at Sodium which is one before Magnesium. Your answer would be almost the same, but instead it would look like this, : 1s^2 2s^2 2p^6 3s
-A Meldrick Mendoza productions : )
Thursday, October 21, 2010
Bohr Models (I forgot to submit this last class)
-Atoms are electrically neutral
-Two Different models can be used to describe electron configuration.
1. Bohr Model
2. Energy Level Model
-Electrons occupy shells which are divided into orbitals
What information you need to make a model:
# of protons (atomic number)
# atomic mass
# of neutrons > this is found by subtracting the mass number by the atomic number.
Number of electrons each shell can contain (up to 4)
1. 2e
2. 8e
3. 8e
4. 18e
-Electrons are paired in Bohr Diagrams except on the first shell; they are on opposite sides.
Examples:
Bohr Diagram of sodium
http://www.green-planet-solar-energy.com/images/sodium-bohr.gif
Jomar Delos Santos
-Two Different models can be used to describe electron configuration.
1. Bohr Model
2. Energy Level Model
-Electrons occupy shells which are divided into orbitals
What information you need to make a model:
# of protons (atomic number)
# atomic mass
# of neutrons > this is found by subtracting the mass number by the atomic number.
Number of electrons each shell can contain (up to 4)
1. 2e
2. 8e
3. 8e
4. 18e
-Electrons are paired in Bohr Diagrams except on the first shell; they are on opposite sides.
Examples:
Bohr Diagram of sodium
http://www.green-planet-solar-energy.com/images/sodium-bohr.gif
Jomar Delos Santos
Monday, October 18, 2010
Bohr's Model
- Bohr (1920s)
-Rutherford's model was inherently unstable
-Protons and electrons should attract each other
-Matter emits light when it is heated (blackbody radiation)
-Light travels as photons
-The energy photons carry depends on their wavelength
-Bohr based his model on the energy (light) emitted by different atoms
-Each atom has a specific spectra of light
-To explain this emission spectra Bohr suggested that electrons occupy shells or orbitans
-Rutherford's model was inherently unstable
-Protons and electrons should attract each other
-Matter emits light when it is heated (blackbody radiation)
-Light travels as photons
-The energy photons carry depends on their wavelength
-Bohr based his model on the energy (light) emitted by different atoms
-Each atom has a specific spectra of light
-To explain this emission spectra Bohr suggested that electrons occupy shells or orbitans
Bohr's Theory
-Electron's exist in orbitals
-When they absorb energy they move to a higher orbital
-As they fall from a higher orbital to a lower one they release energy as a photon of light
Here's a picture of a couple of Bohr models: http://lapse.nerdvana.org.au/comedy/pics/atom-bohr.gif
Thursday, October 14, 2010
Four Element Theory
wetness
water wind
coldness hotness
earth fire
dryness
-the four elements theory lasted for about 2000 years
-it's not a scientific theory because it could not be tested
-in 300BC Democritus said atoms were invisible particles
-this was the first mention of atoms in history
-not a testable theory only a conceptual model
-no mention of any atomic nucleus
-cannot be used to explain chemical reactions
Lavoisier (late 1700's)
-law of conservation of mass
-law of definite proportions (water is always 11% H and 89% O)
Proust (1799)
-if a compound is broken down into its constituents the products exist in the same ratio as in the compound
-experimentally proved Lavoisier's laws
Dalton (early 1800's)
-atoms are solid, indestructible spheres (billard balls)
-provides for different elements(these would be different spheres)
-based on the law of conservation of mass
-having a molecule(atoms combine in whole number ratios) explains the law of constant composition
J.J Thomson (1850's)
-raisin bun model
-solid, positive spheres with negative particles embedded in them
-first atomic theory to have positive (protons) and negative (electrons) charges
-demonstrated the existence of electrons using a cathode ray tube
Rutherford (1905)
-showed that atoms have a positive, dense center, with electrons outside it
-resulted in a planetary model
-explains why electrons spin around nucleus
-suggests atoms are mostly empty space
Helpful Links
four element theory-https://reich-chemistry.wikispaces.com/Fall.2008.MMA.McCarthy.Timeline
J.J Thomson-http://www.aip.org/history/electron/jjhome.htm
-Kerr Pili
Tuesday, October 5, 2010
Sodium Chloride Lab
On October 5th, 2010, our class did an experiment about water and salt (Sodium Chloride).
Our experiment was, how much salt can dissolve in 200mL of water.
We had four trials, and in each trial we have different amount of water.
The first trial was with 10mL of water and the mass of salt we got was 0.38g (Yeah, we got really results.)
Second test with 20mL of water, the mass of the salt was 1.03g.
Third test with 40mL of water, the mass of salt was 1.53g.
Our last test with 50mL of water, we got 2.11g of salt.
-Meldrick Mendoza Productions : )
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