Welcome once again to The Chemical Elements! Today, I thought I'd do an element common in peoples' lives: sodium! Let's get started!
If you are confused by any of these terms, go to the glossary!
Facts about sodium
Electron configuration: [Ne] 3s1
Atomic number: 11
Key isotope: 23Na
Relative atomic mass: 22.990
Melting point: 97.794 °C
Boiling point: 882.940 °C
Electronegativity: 0.93
1st ionisation energy: 495.845 kJ mol-1
Sodium, the first element of the third row... what a common element in our lives! When it takes the form of sodium chloride (NaCl), we sprinkle it on our chips, our rice and one our vegetables! We use it for brining meat, we use it on the road to de-ice it and we even use it in cooking to stop things from sticking together! As a mineral, it is known as halite. It absorbs water from everywhere (even the air!) and this has led to its use as a preservative - it keeps water away from bacteria and even draws water out of them!
But salt isn't the only interesting thing about sodium. As a pure element, it is a metal - part of group 1, the alkali metals. So when you place it in water, an interesting reaction occurs. Here it is:
2Na + 2H2O = 2NaOH + H2
Or in other words,
sodium + water = sodium hydroxide (caustic soda) + hydrogen
Most chemists would call the reaction exothermic. Or in other words, explosive. If you put a large enough chunk in, due to the hydrogen gas and the heat, it even sets on fire! It's also fairly soft and can be cut with a knife, unlike most other metals.
Most of sodium's compounds find use somewhere. Compounds like sodium ferrocyanide (Na4[Fe(CN)6]) are used as food additives. (Don't worry, it's not toxic - they wouldn't use it otherwise.) Or sodium bircarbonate (also known as sodium hydrogen carbonate), NaHCO3, used as a raising agent or as a treatment for bee stings!
Sodium is an awesome metal - every bit as awesome as its heavier counterpart, potassium! I'll cover that another time, but for now, I'll see all of you next week! Bye for now!