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Remembering Common Ions for Transition Metals - Concept
Tips on remembering the Common ions for Transition metals. So it's easy actually to remember the common ions for things in Group 1 and Group 2; the Alkali, and Alkaline earth metals. Alkali metals are +1, Alkaline earth metals are +2. That's fairly easy. Those are the s-block over here.
Then we have the things in the Transition Metal. Actually, the reason that you can call Transition metals, is because; a, you're transitioning from very characteristic metals to non-metals. But also, because their oxidation numbers or common ion states are changing. They can be one or the other. They can transition between one common ion, and another. A lot of times they have two, and your teacher asks you to remember them, and memorize them, and yet it's really overwhelming, and really tough.
We're going to think of tricks on how we can do that. Here is the d-block. I had at end it goes from d1 all the way to d10 which is also another name for Transition metal block. So it ends here. Let me start with our representative metalloid area, which is the P1. This is also called group 1.
We know that the ions in group 3 are +3. Like Aluminium is always going to be a +3 charge. What about these guys in the middle? They're single mnemonic devices or some things, and ways we can remember the charges they are.
Aluminium is up here right diagonal cutting corner from Zinc. Aluminium is a +3 we know that, because it's in the Group 3. So Zinc is always going to be a +2 and notice it's a diagonal. So 3 plus 2, and Silver will always be +1. That means, that Zinc and Silver you do not have to say when you're naming them their oxidation numbers.
In any other Transition metals, you have to tell which ion you're using using the Roman Numerals. Zinc and Silver you do not, because Zinc is always +2. Silver is always +1. Aluminum is always +3, 2, 1. Easy to remember.
Cadmium actually is most likely always going to be +2 as well. Sometimes it changes, but most likely it's always going to be +2. So this area there always will be common Ions. It's easy to remember.
Going over to Copper, it's +1 or +2. So it's kind of between 2, and 1 here next to Zinc above Silver. So it's +1 or +2. Those are going to be the two oxidation states for Copper.
Now Nickel, we're familiar with Nickels. Nickels are 5 cents in other words. So Nickel, the two oxidation numbers actually add up to 5; +2 and +3. 2 plus 3 is 5, it's easy to remember it, it's a Nickel. In fact Nickel, Cobalt, Iron, and Chromium, we'll talk about Manganese in a second, are also always +2, +3. Think about they add up to 5. +2, +3, and +2, +3.
Manganese is always a +2. So if you start from Nickel, and think 5 cents and you go to the left 5, all of those are +2, +3 except Manganese which is only +2. You always have to have an exception in Chemistry, don't you? There's exceptions everywhere. Here is one of them.
The rest of these are not common. Like the ones that are semi-metallic you're not going to see much your Chemistry classes. You'll deal with them more when you're talking about upper level chemistry or different types of metals, Metallic Chemistry. But these are the ions you're going to see in class most often.
Tin, and Lead; Sn, and Pb, are not in the Transition metal area meaning they are not in the d-block. However, they are transition metals. They do have their own charges that you're going to have to remember. Tin is a +2, or a +4. The same as Lead. Lead is +2, or +4.
Think about it like everything in Group 3 is always +3. These are always +3. So Tin straddles between being a +2 and being a +4, which is the group that it's in. So that hopefully that will help you in terms of remembering that Tin and Lead are +2 and +4.
Let's look at why this is exactly the way it is. Let's look at why is Iron, for example going to be +2 and +3, why? So let's look at that. When you think about ions, and what's going on with electrons, you have to write up Electron Configuration. So let's just write out just Iron by itself, just 26 electrons.
Doing the Noble Gas configuration, I'm going back and it's Argon [Ar] 4s23d6. Now I'm going to tell you, and you should have learned this when you were learning the electron configuration, that orbitals like to either be 1/2 filled or fully filled to be the most stable. So knowing this 3d, so d-block has 10 electrons, being half filled is 5 being fully filled is 10.
Metals always lose electrons. So this can easily be 1/2 filled by taking away its d6. But before we can take away one of the electrons from d6, and making it d5, when we actually remove electrons, we remove from that valance electron area first. The valence electrons are from the outermost shell here. So this electron have to go before electron, and then before this electron. So to make it Iron; Fe +2, 24 electrons, it's going to be Argon [Ar]3d6. Just getting rid of these guys.
If you're talking about Iron;Fe+3, it's 23 electrons. It's going to be Argon [Ar]3d5. So these are the reasons why it's +2 and +3. This is just getting rid of valence electrons. This actually is making it a bit more stable, and making it a 5
One more shot. Let's look at Copper. Copper is +1, and +2. So Copper's Electron Configuration, copper has 29 electrons. It's Argon [Ar]4s23d9. Actually Copper is an exception. Copper is not this, because we've agreed that it's 1/2 filled or fully filled. One of these s-electrons is going to go into the d-orbital making it d10 which is fully filled, and that means s orbital is 1/2 filled.
So this is Argon or s1 1/2 way filled 3d10, fully filled, again very stable. So this is the atom of Copper meaning not charged. If we charge it, we said it's either +1 or +2. If it's +1, we take away its valence electrons, and we're going to say Argon; [Ar]3d10. The very same way we took away this.
If we say it's Cu+2 which is 27 electrons, we're going to go back to it's original state before it become a thief and stealing an electron, the d orbital stealing electron. We're going to go back and take both of these away. So it's going to be Argon [Ar]3d9 for Cu+2.
It gets complicated especially when you get to other ones that aren't so obvious. Especially when you get to the d-block, that I did mention here, but this is where they come from. And a lot of Physical Chemists this is what they do for a living. They try and figure out what makes it most physically possible for the electrons, and why they're in certain states that they are.
So hopefully this helped understand why these ions exist, and why they can be in several different transition states. Also helps you memorize the main ones in the transition metal. The different charges. So hopefully that helped.