LOOKING AT IONS
We've talked about ions before, it's time to get down to basics. Ions are atoms with extra electrons, or they may be missing electrons. A normal atom is called NEUTRAL. That is when an atom has a number of electrons equal to the ATOMIC NUMBER. Normally atoms want to have their shells filled.
So what do you do if you are a Sodium atom? You have eleven electrons. One too many to have your shell filled. The answer, find another element who will take that electron away from you. In comes Chlorine. Chlorine will take that electron away, leaving you with 10 electrons, and two filled shells. You are a happy atom. But you are also an ion, missing one electron. A Sodium ion.
(D) So you've become a Sodium Ion. Now you have ten electrons. That's the same number as Neon. But you aren't Neon. Since you're missing an electron, you aren't really a complete Sodium atom. You are now something completely new. An ion.
Your whole goal as an atom was to become a "Happy Atom". Now you have filled shells. You are stable. What do you do that's so special now? Now that you have given up the electron, you are now quite attractive, electrically. Other electrically charged atoms (ions) are now taking a look at you seeing you as a good partner to bond with (that's where Chlorine comes in).
Don't get worried, ELECTROVALENCE is just another word for something that has given up its electron and become an ion. If you look at the periodic table you might notice that elements on the left side usually become positively charged ions and elements on the right side get a negative charge. That means the left side has a positive valence and the right side has a negative valence.
We talk about ionic bonds in CHEM4KIDS. Scientists also call ionic bonds electrovalent bonds. So that mean the two main types of bonding are COVALENT and electrovalent. Ionic bonds are really just groups of charged ions held together by electric forces. Scientists call these groups IONIC AGGLOMERATES.
When they are in the presence of other ions the electrovalent bonds are weaker because of outside electrical attractions. Take Sodium chloride (Salt) for an example. Salt is a very strong bond when it is sitting on your table. It would be nearly impossible to break those ionic bonds. But if you put that salt into some water, the bonds break really quickly because of the electrical attraction of the water. Now all you have are Sodium and Chloride ions. So remember that ionic bonds are normally strong, but very weak in water.
FARADAY CHARGES UP!
Michael Faraday did a lot. He started as a chemist, and then started doing work in Physics. He is most famous for the work he did in electricity. He did work with magnetic elements like iron. One of the big ideas he worked on was INDUCTION. Faraday showed that if you send and electric current through something, you will create a magnetic field (an electromagnet). He also show the opposite to be true, if something has a magnetic field, it can produce a current of electricity.
Oh yeah, he did Chemistry stuff too. He liquefied gases and discovered new compounds. In 1834 he worked with electricity by separating Sodium (Na) and Potassium (K) from solutions using ELECTROLYSIS. That's where you run a current through a solution and different elements move towards the different electrodes (it's all based on what charge the atoms are). You'd think his hair should be standing on end with all that electricity.