One week until Christmas Day!
Hello, everybody! Today, I thought I'd do another of these posts - it's been ages since I did one of these, hasn't it? Well then, let's get going!
If you are confused by any of these terms, go to the glossary!
Facts about chlorine
Symbol: Cl
Electron configuration: [Ne] 3s23p5
Atomic number: 17
Key isotopes: 35Cl, 37Cl
Relative atomic mass: 35.45
Melting point: -101.5 °C
Boiling point: -34.04 °C
Electronegativity: 3.16
1st ionisation energy: 1251.186 kJ mol-1
Electron configuration: [Ne] 3s23p5
Atomic number: 17
Key isotopes: 35Cl, 37Cl
Relative atomic mass: 35.45
Melting point: -101.5 °C
Boiling point: -34.04 °C
Electronegativity: 3.16
1st ionisation energy: 1251.186 kJ mol-1
Chlorine is an element many people have heard of - usually in the context of swimming pools, where a chlorine compound (usually hypochlorous acid [HClO] or sodium hypochlorite [NaClO]) is in the water to act as a disinfectant. This works because chlorine kills bacteria on its own. (Also, if you have too much of it, it kills people too. That's why it was used as a weapon in the First World War.)
When chlorine is found in nature, it is always in the form of chloride [Cl-]. Chlorine gets its killing power (for lack of a better term) from the fact that it is one electron away from being in a stable 'noble gas configuration'. And it wants that electron... and will get it from anywhere possible. Including cells.
But when it gets the electron, it becomes its chloride form, which is far less reactive and prefers to sit around and do nothing. (Like me!)
Chlorine is an essential element in the human body - our stomach secretes hydrochloric acid [HCl·H2O] to fill it and to make food easier to digest. Chloride ions are present inside and outside the cells as electrolytes in order to balance the positive charge of all the sodium and potassium ions in our bodies.
In the past, chlorine was commonly used in order to make chloroform [CHCl3], an anaesthetic; and carbon tetrachlroide [CCl4], a dry cleaning solvent. However, both of these compounds can cause liver damage, so they are no longer in use.
The most common mineral mined for chlorine is halite - or sodium chlordie [NaCl]. As I'm sure many of you know, halite is thus also table salt! Chloride is also found in carnallite [KMgCl3·6H2O]
and sylvite - or postassium chloride [KCl]. Chlorine gas is produced on an industrial scale by electrolysis of brine (running an electric current through a solution of salt).
Also, if you pour molten salt [NaCl] into water, it explodes.
I have some sad news to share with everybody...
Angela, my school's speech and language therapist, is leaving us on Wednesday - the last day of term. So I wanted to just say thank you, Angela. Thanks for all you've done for us!
Anyway, I shall see you all in a week's time... on Christmas Day! See you then!