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211'10 FTW!
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Friday, July 31, 2009 @ 10:31 PM
There's chemistry. HELLO EVERYBODY. Somethings so revise. Hah. ELEMENTS Definition: An element is a pure substance (made up of only one substance, without mixing with other substances) that cannot be broken down into simpler substances by chemical reaction, because it is the simplest form of matter. Hydrogen - H Helium - He Lithium - Li Beryllium - Be Boron - B Carbon - C Nitrogen - N Oxygen - O Fluorine - F Neon - Ne Sodium - Na Magnesium - Mg Aluminum - Al Silicon - Si Phosphorous - P Sulfur - S Chlorine - Cl Argon - Ar Potassium - K Calcium - Ca Iron - Fe Cobalt - Co Nickel - Ni Copper - Cu Zinc - Zn Bromine - Br Silver - Ag Iodine - I Gold - Au Mercury - Hg Lead - Pb Elements can be classified as METALS of NON-METALS. Metals: 1) Good conductors of heat. 2) Good electrical conductors. 3) Ductile - Can drawn into thin wires 4) Malleable - Can be beaten into sheets without breaking. Non-metals: 1) Poor eletrical conductors. 2) Brittle Diamonds and graphite are forms of carbon. Compounds: Made up of two or more elements chemically combined together. These are a few examples of compounds. Copper + Zinc = Brass Copper + Tin = Bronze Hydrogen + Oxygen = Water Nitrogen + Oxygen = Nitrogen Oxide Sodium + Chlorine = Sodium Chloride (Common Salt) Carbon + Hydrogen + Oxygen = Sugar Silicon + Oxygen = Sand Carbon + Hydrogen + Alcohol (Oxygen + Hydrogen with H6) = Ethanol Carbon + Hydrogen = Methane A compound may be broken down into simpler substances by chemical methods. Heat or electricity is usually required. Seperation techniques notes coming up tomorrow, if anyone wants it. Atoms Definition: Smallest most indivisible part of an element. Atoms are made up of: -Protons (forms the nucleus) -Neutrons(forms the nucleus) -Electrons (aroud the nucleus) Protons: Its relative mass is 1. Its relative electric charge is +1. Neutrons: Its relative mass is 1. Its relative electric charge is 0. Electrons: Its relative mass is approx. 0.0005 or 1/1836. Its relative electric charge is -1. The nucleus has a positive charge because of its protons. An atom is electrically neutral, therefore, the number of electrons = the nummber of protons. The nucleus has a positive charge cos' of its protons. The elctrons are negatively charged. Therefore, they are attracted to the positive nucleus. Because, (+)+(-)= attract! Opposites attract. THE NUCLIDE NOTATION OF NEUTRAL ATOM This is pretty important. Okay, I can't really put the symbols here so you can imagine it with my description. First, write the ELEMENT SYMBOL on the right hand side. Then, on the left side of the ELEMENT SYMBOL, for the top left corner, write the MASS NUMBER of the element. Then, on the bottom left corner, write the ATOMIC NUMBER of the element. That's the thingy I've been talking about. MASS NUMBER: The number of NEUTRONS+ the number of PROTONS. ATOMIC NUMBER: The number of PROTONS. ELEMENT SYMBOL: The element symbol. (example: Cl, B, F) ISOTOPES Isotopes are atoms of the same element with the same number of protons, yet with the different numbers of neutrons. (e.g. hydrogen) (Paiseh. I'm pretty confused about isotopes myself. But maybe you understand? If you do, please explain thx. But I'm 99% sure the information here is correct.) Why? Nucleon number is the sum of protons and neutrons. Therefore, different number of neutrons will give a different nucleon number. |