Complex sentence: The valence electrons can be counted using a Lewis electront diagram as shown at the right for carbon diooxygen shares four electrons with the central carbon, two (shown in red) from the oxygen itself and two (shown in black) from the carbon.
Split into simpler sentences: The valence electrons can be counted using a Lewis electron dot diagram as shown at the right for carbon dioxide. In carbon dioxide each oxygen shares four electrons with the central carbon, two (shown in red) from the oxygen itself and two (shown in black) from the carbon.