L3 L.D.S.

• LEWIS DOT STRUCTURE

  • Gilbert Lewis in 1916

  
• Lewis Dot Structures

  • A.ka. Lewis electron dot diagram, electron dot diagram, Lewis diagram, Lewis structure
  • A representation of the valence electrons of an atom that uses dots around the symbol of the element.
  • Shows structural formulas for compounds
  • Arrangement of atoms and bonds within a compound.

  
• • Electron-dot symbols are derived by placing valence e- (represented by dots) to the right, left, top, and bottom of the element’s symbol.
  • Starting on any side, we place one dot at a time until there are up to four unpaired e- around the symbol.
  • If there are more than four valence e- for an atom, the remaining e- are added – one by one – to the unpaired e- to form up to four pairs.

  
• • There is no set convention for the placement.
  • For example, chlorine atoms could be.

  
• • Noble gases have an octet (except helium, which has only 2 e- total), and they are so stable that they rarely form chemical bonds with other atoms.

  
• • Uses valence electrons
  • One dot = one valence electron
  • One dash = a covalent bond = two electrons
  • These dots are (COMMONLY)
  • Arranged to the right and left and above and below the symbol, with no more than two dots on a side. 
  • The order in which the positions are used does not matter. 
• OCTET Rule

  • States that when atoms of elements combine to form compounds, they tend to lose, gain, or share electrons to achieve the same electron arrangement as the noble gas nearest them in the periodic table.
• REVIEW AND ANALYZE

  How to Draw 

  Lewis Dot Structures

  1. Find your element on the periodic table.
  2. Determine the number of valence electrons.
  3. This is how many electrons you will draw.
• • Find out which group (column) your element is in.
  • This will tell you the number of valence electrons your element has.
  • You will only draw the valence electrons.

  
• • Each column is called a “group”
  • each element in a group has the same number of electrons in their outer orbital, also known as “shells”.
  • The electrons in the outer shell are called “valence electrons”

  
• L.D.S

  
• Lewis Dot Structures

  1. Write the element symbol.
  2. Carbon is in the 4th group, so it has 4 valence electrons.

  3. Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol.