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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