Counting Valence Electrons Quiz

How is the number of valence electrons in an atom determined using the periodic table?

• By the row the element is in

• By the column the element is in

• By the atomic number of the element

• By the atomic mass of the element

What is the total number of valence electrons in a molecule with one hydrogen, one nitrogen, and three oxygen atoms?

• 20

• 18

• 24

• 26

If a molecule has a positive charge, what should you do when counting valence electrons?

• Double the number of electrons

• Ignore the charge

• Subtract electrons equal to the charge

• Add electrons equal to the charge

For a molecule with a negative charge, how do you adjust the valence electron count?

• Ignore the charge

• Add electrons equal to the charge

• Subtract electrons equal to the charge

• Divide the number of electrons by the charge

What is the adjustment in valence electrons for a sulfate ion (SO4^2-)?

• Add 2 electrons

• Subtract 2 electrons

• Add 1 electron

• Subtract 1 electron