13.1 Electrons and Chemical Bonds

Valence Electrons Valence electrons: electrons in the outermost (highest) energy level

Valence Electrons – a trick 1 7 8 2 3 4 5 6 Look at Group Numbers!

How many Valence Electrons? Nitrogen (N) Carbon (C) Potassium (K)

Lewis Dot Diagrams To draw a Lewis dot diagram: A Lewis dot diagram shows the element symbol surrounded by dots representing the valence electrons. Example: To draw a Lewis dot diagram: Determine the number of valence electrons Write the symbol and add dots for valence electrons

Valence Electrons Practice Now draw the Lewis dot diagrams: Element Name Symbol Number of Electrons Number of Valence Electrons Lewis Dot Diagram Nitrogen Oxygen Fluorine Neon N 7 5 O 8 6 F 9 7 Ne 10 8

Lewis Dot Diagrams on PT Group # = # valence electrons Transition metals are weird, ignore for now!

Chemical Bonds Chemical bonds are formed only between the electrons in the highest unfilled energy level.

Types of Chemical Bonds A chemical bond forms when atoms transfer or share electrons. Covalent Bonds – atoms share valence electrons Ionic Bonds – atoms transfer valence electrons

Dogs Teaching Chemistry! https://www.youtube.com/watch?v=_M9khs87xQ8

Covalent Bonds Form between nonmetals Share electrons

Ionic Bonds Form between metal and nonmetal Electron(s) transferred from metal to nonmetal Ions are formed Bond = attraction Sodium loses an electron and becomes a positively charged ion Chlorine gains an electron and becomes a negatively charged ion

Chemical formulas A chemical formula tells the ratio of atoms of each element in the compound.

Lewis Dot Diagrams EXIT SLIP Answer the following questions about phosphorous: How many total electrons does phosphorous have? How many valence electrons does phosphorous have? What is the Lewis dot diagram for phosphorous?