 Okay, so let's try this one. It says write the formula for the following compound sodium hexanitrocobaltate 3. Okay, so when we look at this name Well, hopefully since we're on the complex Coordination complex chapter we thinking we've got a coordination Okay, so Exanitrocobaltate. Okay, so that means that this is something that's negatively charged Okay, and it's attached to the positively charged sodium ions. Okay Nitro right, so Nitro is the ligand You got that right that is the n o 2 minus Okay, so the nitrate remember when they're negatively charged we change it to the oh, so we call it Nitro When it's a ligand, okay, how many do we have hexa? six of them, okay, and what's the atom that's in the middle? Cobalt, right, okay, so let's just draw what we know now, so we've got a cobalt atom and Around that cobalt atom we've got n o 2 Minuses right and we got six like that Okay, so if we've got six remember, this is a minus one if we've got six minus ones How many total minuses do we have? Six times minus one have what's the total negative charge negative six right, but our total Oxidation number for cobalt here is plus three. Okay, so if we have negative six plus three What's going to be our charge here three negative three negative three right? Like that does that make sense okay because we got a plus three here and six minus ones Okay, so that's going to be overall negative three so sodium. What's its charge from the periodic table? Plus one okay, so we're going to have this and we're going to add it to this complex ion So how many positive ones do we need to totally counteract that negative three so we're going to have three of them like that So when we put this all together, it's going to look like this NA3 CO n o 2 Since let's draw this Any questions on that one that makes sense okay wonderful