[[Matter and Chemical Bonding]]

add or remove valence e according to charge

H stable at a duet 2d
Be stable at a tetrad 4e
B stable at a sextet 6e
all other elements in pe 1 and 2 require octets 8e (common ball)
per 3 and below can go above an octet (common ball)

$po_4^{-3}$