MAKING IT EASIER
Valence Versus Ions
By know, you are probably very confused with valence versus the ions that are created. That is understandable! Let’s review these concepts and actually tie them nicely with a bow to make things easier.
Valence is, as you know, the electrons on the last layer of an atom. Protons and neutrons don’t really do much; they just hold each other tight and hope for the best. But electrons are the wild cards.
One thing that is important is, the inner layers of electrons can’t really connect with the outside world. Why? Ok, imagine you go to a race car event. Would you try to cross the street when all the superfast cars are going? No? Same reason. Electrons are extremely fast and completely fill their layers with movement and energy, and so the only layer that can be touched and interact with other atoms is the outer layer.
Of course, as we saw in a couple of examples, sometimes the layer right below the last kicks some electrons out to make the last layer. Example: an atom that has 11 electrons on the last layer, for instance, will kick off 3 electrons to create a new layer, which will then try to find an atom that needs 3 electrons. This will be usually an ionic bond except for some exception compounds.
Let’s see the trick to figure out valences once and for all!
Valence is, as you know, the electrons on the last layer of an atom. Protons and neutrons don’t really do much; they just hold each other tight and hope for the best. But electrons are the wild cards.
One thing that is important is, the inner layers of electrons can’t really connect with the outside world. Why? Ok, imagine you go to a race car event. Would you try to cross the street when all the superfast cars are going? No? Same reason. Electrons are extremely fast and completely fill their layers with movement and energy, and so the only layer that can be touched and interact with other atoms is the outer layer.
Of course, as we saw in a couple of examples, sometimes the layer right below the last kicks some electrons out to make the last layer. Example: an atom that has 11 electrons on the last layer, for instance, will kick off 3 electrons to create a new layer, which will then try to find an atom that needs 3 electrons. This will be usually an ionic bond except for some exception compounds.
Let’s see the trick to figure out valences once and for all!
The Trick for Valences
On the table above, groups 1, 2, 13, 14, 15, 16, 17 and 18 are pretty special.
Their valences are 1, 2, 3, 4, 5, 6, 7 and 8, respectively!
You can prove this by figuring out the Bohr’s models for every one of the very top atoms (they are very easy).
If you know the valence of an atom, and you know how many electrons makes a stable atom (2 in some instances, 8 in most instances) then you can tell how many electrons are needed to make each atom happy.
So, looking at Mg, you see that it has 2 electrons on the last layer; it wants to dump those and become a positive ion (+2). This way it can bind with Oxygen, which has a valence 6. How does this happen? A valence 6 means it has 6 electrons on the last layer, and so it needs two electrons to feel good about itself. That means Oxygen is a -2 in terms of bond.
Does it always mean ions will be formed? No! But you will be able to tell what will happen by looking at the atoms you are using. Depending on them, you will be able to tell if it is an ionic bond or a covalent bond.
An ionic bond will always bind a metal to a non metal (like NaCl), while a covalent bond will bind two non-metals (think H2O).
Another cool thing: Every atom on the second period will have two layers of electrons. Every atom on the third period will have three, and so on and so forth!
Let’s check out the charges for the elements:
Their valences are 1, 2, 3, 4, 5, 6, 7 and 8, respectively!
You can prove this by figuring out the Bohr’s models for every one of the very top atoms (they are very easy).
If you know the valence of an atom, and you know how many electrons makes a stable atom (2 in some instances, 8 in most instances) then you can tell how many electrons are needed to make each atom happy.
So, looking at Mg, you see that it has 2 electrons on the last layer; it wants to dump those and become a positive ion (+2). This way it can bind with Oxygen, which has a valence 6. How does this happen? A valence 6 means it has 6 electrons on the last layer, and so it needs two electrons to feel good about itself. That means Oxygen is a -2 in terms of bond.
Does it always mean ions will be formed? No! But you will be able to tell what will happen by looking at the atoms you are using. Depending on them, you will be able to tell if it is an ionic bond or a covalent bond.
An ionic bond will always bind a metal to a non metal (like NaCl), while a covalent bond will bind two non-metals (think H2O).
Another cool thing: Every atom on the second period will have two layers of electrons. Every atom on the third period will have three, and so on and so forth!
Let’s check out the charges for the elements:
As you can see, some elements can form more than one charge; usually this will be defined by the problem, so no need to worry about it. The basic thought process is that the charge will be positive until it reaches group 14; as this group has 4 electrons on the last layer, it can either give or take 4 electrons, and very commonly likes to do a covalent bond with other elements, so that it can easily reach 8.
That's all for now! :) Hope this helps!
That's all for now! :) Hope this helps!
