DO NOW Turn in Third Electron Configuration Practice. Turn in Burning Balls of Color lab Get our your Electron Configuration notes sheet and turn to the back.

VALENCE ELECTRONS Using an electron configuration, you can determine the valence electrons: 1s22s22p63s23p5 Find the highest energy level. Count the electrons associated with that energy level. So this element has 7 valence electrons (What is its name?). 3 2 + 5 = 7

ELECTRON CONFIGURATION: IONS For atoms that occur as ions, the electron configuration can also be written. First, write the regular electron configuration for the element. If the ion is positive, take away electrons. If the ion is negative, add electrons to the highest partially filled energy level.

EXAMPLES Na Na+1 1s22s22p6   F F-1 1s22s22p6 Al Al+3 1s22s22p6   H H-1 1s2

ELECTRON DOT DIAGRAMS To write an electron dot diagram, follow these steps: Write the symbol for the element (symbolizes the nucleus and all inner energy levels). Write the electron configuration for the element. Select the electrons in the outermost energy level. Use the HIGHEST energy level number. Each side of the symbol represents an orbital. Draw the dots on the appropriate sides to represent the electrons in that orbital. It is important to remember which electrons are paired and which are not.

ELECTRON DOT DIAGRAMS s s X p p p p

PRACTICE Sodium valence electrons: Silicon Magnesium Chlorine

TO DO Valence, Ion, and Electron Dot Practice – due tomorrow.