What is the total number of valence electrons in a sulfide ion in the ground state?
8 because sulfur has 6 valence electrons and when it becomes sulfide it gains two electrons making it 6+2=8.
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.
If its positive it tells u that it has that number of valence electrons. If negative it tells you that it requires that number of electrons to make the valence electrons filled up/stable. If you know which Ion it is, you know the number of valence electrons of the neutral Atom. It corresponds to the group in the periodic table, the element is in. For example: Mg. It's in group 2, so it has 2…
You can determine how many valence electrons an atom has by what family the element of the atom is in. For instance, if the element is in family 8A, the number of valence electrons will be 8. Or, if the element is in family 2A, the number of valence electrons for the atom will be 2. So, whatever number family the atom is in, the number of valence electrons equals that.