_:nd220e2a8ce394febb3754c7c38d87507xb0
<http://schema.org/name>
"To find the oxidation number of the ions that compose an ionic compound, remember… The elements from group 1 will be +1, group 2 will be +2, group 13 will be +3, group 15 will be -3, group 16 will be -2, and group 17 will be -1."
<http://slideplayer.com/slide/8843812/>