An Introduction to Chemical Elements
By: Natasha Brackett
Elements
• Pure substance• Only ONE type of atom• Add together to make compounds• Make up all chemical matter• All known elements are in periodic table
http://en.wikipedia.org/wiki/Chemical_element
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Protons
• + 1 Positive Charge• Found in Nucleus• Atomic Number• Defines Elements by Atomic Number
http://en.wikipedia.org/wiki/Protons
Electrons
• - 1 Negative Charge• Cancels out Proton• Smallest particle in an atom• Found in Cloud around Nucleus
http://en.wikipedia.org/wiki/Electron http://chemistry.about.com/od/atomicmolecularstructure/a/aa062804a.htm
Electron Shells
• Only fixed number of electrons per Shell• Shells fill from inside out
http://en.wikipedia.org/wiki/Electron_shell
2 8 8
Nobel Gases
• Last electron shell is full• Not very reactive
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Neutrons
• No Charge• Balance atoms• Found in Nucleus• Cause Isotopes
Svdmolen/Jeanot, Public Domain
Individual Elements
http://education.jlab.org/qa/pen_number.html
Atomic Weight
• Measured in Atomic Mass Units (AMU)• Protons and Neutrons– Electrons are too small
• Weighted Average of All Isotopes
http://education.jlab.org/qa/pen_number.html
Example
• A) What Atom and Atomic Symbol?
• B) How many protons?
• C) How many electrons in a neutral atom?
• D) How many Neutrons?
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A) What atom/ atomic symbol?
Titanium/ Ti
B) How many Protons? 22
C) How many Electrons? 22
D) How many Neutrons?
• Atomic Weight ≈ 48 Amu • Take Atomic Weight and subtract atomic
number/ amount of protons• The electrons are too small
• Number of Neutrons is 26€
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