So what brought this on. I was directed to an article on BBC World Magazine on chlorine. In this article the author says “Vast amounts of electricity are used to tear apart the sodium and chlorine atoms in salt molecules through the process of electrolysis.” Now I am pretty sure that on his visit to the plant the author did encounter the word “ions” from those chemists showing him around.
So why didn’t’ he use “ion”. Now I hope he did not think that the general public does not know the word. This is what is so annoying; every teacher of chemistry knocks themselves senseless trying to get students to use the word. I refuse to think that he thought it was out of the range of most people.
“Ion” was coined by the great Michael Faraday in 1834 to represent some charged, wandering particles which allowed an electric current to flow through a liquid medium. Now it is taught to 11-16 year old students and beyond but my students never liked using the word. It had an electric charge for a start (that is physics!) and ion had different amounts of charge and they were positive or negative. “Positive means more electrons?” “No more protons, negative means more electrons”, “Is this logical, sir”. Ionic equations were a real turn off. However, students did like the molecule. This was neutral. They could make nice shapes with their Molymod models. One shape even looked like a dog.
I said to my 9-year old grand-daughter what she was doing in science at school. “Particles” Rosa said. “Do you know their names?” “Yes, atoms and molecules”. “What about ions? “Never heard of them”. “Well upset your teacher and ask about ions as well”. I suspect the teacher has forgotten all about them as well. Just like the author of that piece in the BBC magazine.
That article reminded of all the times I had had corrected similar statements from students when marking. That sentence would have been marked wrong in every GCSE exam (I hope) and a School Inspector would bring the school into special measures if he/she heard it, after all they are experts in their field.
“Ions” can conjure up the mysterious as well, that they are used in alternative medicine. It doesn’t take much to find this on the web.
Negative ions generally in natural settings in greater numbers than positive ions. For instance, negative ions are generated by moving water – rivers, waterfalls, crashing waves, even showers and fountains – and the presence of negative ions is actually used to identify potential sources of water on other planetary bodies, like Enceladus and Titan.
“Ions” appear in science fiction as weapons (the ion cannon in Star Wars), they are involved in hyperspace travel although there is an “ion drive” rocket motor.“Ion” sounds masculine as in Ian, Iain, Eóin, Ioan, etc. (I am on dangerous ground here, I had better stop.)
If the word “ion” is used at primary a school level then at least it might enter the long term memory of some students and will not be such a strange word to them when they meet it again at secondary school. I suspect Y6s will not really understand the word “molecule” but they still use the word. Rosa loves saying it; it sounds grown-up and really scientific.
The area of conductivity has disappeared from A level chemistry (units are too hard, I suspect) and often it is mentioned KS3 and 4 with ionic bonding. It is usually carried out with electrolysis in mind rather than electrical conduction (that is physics). Ions are used in the formation of precipitates. Precipitation: that is magic isn’t it, two clear liquids and abracadabra, you get a yellow suspension. Oh then there is the problem saying the “Iron ions are attracted …” which was not a problem when we talked about ferrous and ferric ions. (Bring on the “when I was a lad” brigade”.)
Chemist teachers know that interpreting the visible with the invisible is difficult. I need energy to hold bar magnets together with similar poles but magnets of opposite poles can come together spontaneously. I just hang on to that model in my head and a lot of chemistry slots into place. I comb my hair and place the comb near water from a dripping tap. The flow is defected towards the comb. Water molecules are polar, there is a positive and a negative side cause by a drift of electrons within the molecule. Water be attracted to positive and negative ions Some ionic solids are soluble. Some are not. It is all a question of balancing the attraction between positive and negative entities..
Oh but then to see “sodium chloride molecules” in the BBC magazine written by a student from a top University. What do I pay my license fee for? Forty years of in chemical education down the drain.
However, perhaps we could new arrivals at the chemists’ ball. “Mr and Mrs Ion and their very attractive daughters, Cat and An. “Mr and Mrs Kane and their son, Al…” (Editor: that’s enough!)