for hexaamminecobalt(III)chloride, [Co(NH3)]6Cl3, the early bonding theories allowed only three other atoms to be attached to the cobalt, because of

for hexaamminecobalt(III)chloride, [Co(NH3)]6Cl3, the early bonding theories allowed only three other atoms to be attached to the cobalt, because of its "valence" of 3. Here, could you tell me what the "valence"means? How to calculate it?

For hexaamminecobalt(III)chloride, [Co(NH3)]6Cl3, the early bonding theories allowed onlythree other atoms to be attached to the cobalt, because of its "valence" of 3. Here, could you...