What is the predicted number of valence electrons in barium?
2 is the standard number of valence electrons
Valence electrons describe the number of available electrons for bonding. The group number describes outermost electron. The elements in same group has same valence electrons. The number of electrons available for bonding are the valence electrons. In an element, the group number is equal to the number of valence electrons. So the number of electrons available for bonding can be identified by the group number.