Elements

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Elements Atoms
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An atom refresher

• Matter is anything that takes up space and has
  mass.
• All matter is made of atoms
• Atoms are the building blocks of matter, sort of
  how bricks are the building blocks of houses.

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An atom refresher

• An atom has three parts
• Proton positive
• Neutron no charge
• Electron negative
• The proton neutron are found in the center of
  the atom, a place called the nucleus.
• The electrons orbit the nucleus.

Picture from http//education.jlab.org/qa/atom_mod
el_03.gif
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What are elements?

• Elements are made of only one type of atom
• Elements are the alphabet to the language of
  molecules.
• Elements make molecules
• Elements are made of atoms. While the atoms may
  have different weights and organization, they are
  all built in the same way.

Information picture from Chem4kids at
http//www.chem4kids.com/files/atom_structure.html
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Graphic from http//education.jlab.org/atomtour/fa
ct2.html
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More about Elements..

• Elements are made of only 1 type of atom
• They are like the alphabet
• Molecule- 2 or more atoms of the same or
  different elements combine
• They are like the words created from letters in
  the alphabet
• Compound- 2 or more atoms of different elements
  join together

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More about Elements

• The periodic table is a list of all of the
  elements that can build matter. Its a little
  like the alphabet of chemistry.
• The periodic table tells us several things

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Periodic Table
Atomic Number Number of protons and it is also
the number of electrons in an atom of an element.
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O
Oxygen
Elements SymbolAn abbreviation for the element.
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Elements Name
Atomic Mass/Weight Number of protons neutrons.
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Bohr Model

• The Bohr Model shows all of the particles in the
  atom.
• In the center are circles. Each circle represents
  a single neutron or proton. Protons should have a
  plus or p written on them. Neutrons should an
  n or zero.
• In a circle around the nucleus are the electrons.
  Electrons should have a minus sign or an e.

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How to draw a Bohr Model

1. Draw the nucleus with circles labeled for protons
   and neutrons
2. Draw energy levels around the nucleus
3. Fill in the energy levels
4. Fill from the inside level out
5. Each level can hold a specific number of
   electrons
6. Electrons should be labeled with an e-

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Nucleus
1st shell
-
-
0

2nd shell

0
-
3rd shell
Adapted from http//www.sciencespot.net/Media/atom
sfam.pdf
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Electrons

• They are found in a cloud surrounding the
  nucleus
• Inside the cloud, electrons are found on ENERGY
  LEVELS based on their energy
• These energy levels can be called shells or
  orbitals
• There is a specific amount of electrons that can
  fit in each energy level
• The electrons in the outer-most shell of any
  element are called VALANCE ELECTRONS

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Electrons

• The lowest energy level is closest to the nucleus
• --It holds 2 e-
• The 2nd energy level holds 8 e-
• The 3rd energy level holds 18 e-
• ELECTRONS FILL THE LEVELS FROM INSIDE OUT.

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Electrons

• Electrons can change levels when energy is added
  to or removed from the atom
• If an e- gains energy it is in excited state
  and moves out an energy level
• If it loses energy it goes in an energy level

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So lets try it.

• How to draw a Lithium atom
• First, look at the Periodic Table
• Second, determine the number of protons (Look _at_
  the atomic number)
• Then determine the number of neutrons (Atomic
  mass atomic number)
• Then determine the number of electrons (Look _at_
  the atomic number)

3 Li Lithium 7
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So lets try it.
Protons 3

3 Li Lithium 7
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Electrons 3 2 in the 1st shell, 1 in the 2nd
shell
Neutrons 4 (7-34)
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Lewis Dot Structure

• The Lewis Dot Structure is a bit different from
  the Bohr model.
• It only shows the element symbol and its outer
  most electron shell.

O




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How to

1. Write the symbol.
2. Start on the right hand side, working your way
   clockwise around the symbol.
3. Try Lithium

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Your activity

• Using the beans (Lentils are electrons, Lima
  Beans are protons, and kidney beans are
  neutrons), create a Bohr model , and then a Lewis
  dot structure model of each of the first 20
  elements. After you have created each model, draw
  each model on your chart.
• Hint to make a chart, use a burrito fold, then
  fold the top down by 1 ½ inches. Unfold, you now
  have 3 columns. Label the columns element, Bohr
  model, Lewis Dot.