What Use is Potassium?

Today, 6 October, in the year 1807 Potassium was isolated for the first time by Sir Humphry Davy in England. The 19th element has so many uses it would be impossible to live without it.

Let's be curious and ask 'what use is Potassium?'

K?

Before going any further let's take a look at the element's symbol, K. Potassium's symbol comes from the neo-Latin word for Alkali, kalium. That in turn comes from the Hebrew word for Pot Ash which is where the name Potassium comes from.

Potassium has the atomic number 19 which means it has 19 protons (positively charged sub-atomic particles found in the nucleus) and 19 electrons (negatively charged subatomic particles 'orbiting the nucleus). The atomic mass of 39.10 is an average of all its isotopes (differing number of neutrons. The most common isotope is ³⁹K, which means it has a total of 39 protons and neutrons, meaning it has 20 neutrons (neutral subatomic particles found in the nucleus).

1% of the average daily radiation dose!

Bananas

It is a well known fact that Potassium is found in bananas. Many people also know that bananas are slightly radioactive. The reason for this is that 0.012% of all potassium atoms are the radioactive isotope ⁴⁰K (meaning 21 neutrons and unstable).

Now, don't start avoiding bananas fearing their radioactivity. Their radioactivity is only 1% of what you receive everyday from naturally occurring radiation, which in itself is tiny.

Pumps

Potassium plays a vital part in our bodies. Our cells contain things called K+/Na+ ATPase pumps. Potassium ions (K+ / potassium with an electron removed) along with sodium ions are used to maintain an electrochemical gradient in your cells. This gradient is used to control the amount of water in your cells.

Agriculture

95% of all industrially produced potassium is used in agriculture fertilizers. The trouble with modern day farming techniques is that plants and soil don't have enough time to replenish with nutrients. That's why many fertilizers contain potassium; the fertilizer replaces lost potassium into the soil which is then taken in by plants. We then eat the plants and use some of the potassium in the pumps explained above.

Industry

A base can neutralise an acid. KOH (potassium hydroxide) is a very common base in industry used to neutralise highly acidic solutions.

Potassium is also found in many dyes and inks in the form of potassium chromate (K₂CrO₄) which is a orangey colour. This is also used in fireworks and matches.

Curious Fact

An informal unit of radiation is the Banana Equivalent Dose (BED)!

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Remember, it is all science. Let's be curious!