Pop some Tags! – Labelling Chemicals with Isotopes

So, you probably know that there are over one hundred different elements on the periodic table. Hydrogen, for example, is an element.

Stylised_Lithium_Atom

This atom has protons (red) and neutrons (blue) in the centre; electrons roam around in the space around it

What are isotopes?

But not all hydrogen atoms are exactly the same. Inside each “atom” of hydrogen, there are particles called protons, neutrons and electrons. These particles are smaller than the atom itself, and are called “subatomic”.

All hydrogen atoms have exactly one proton. If an atom has one proton, it is, by definition, hydrogen. BUT…the number of neutrons can be different from atom to atom. Some hydrogen atoms have one proton (actually, MOST of them do), but some have two and some have three.

Hydrogen can have one neutron (left), two neutrons (centre) or three neutrons (right)

Hydrogen can have one neutron (left), two neutrons (centre) or three neutrons (right)

Who Cares?

The different versions of atom are called “isotopes” (Remember the Simpsons?). Chemically, they react almost identically. The difference is that chemists can tell the difference between them.

We can figure out what this fish eats by studying which isotopes are inside it

We can figure out what this fish eats by studying which isotopes are inside it

Here’s the cool thing: we can use isotopes of elements to track chemicals. For example, we can use different fractions of each isotope of tin to make gunpowders that have a particular “signature” (Source). It’s like the DNA of a chemical mixture, in that we could use it to track whose chemicals were used where. There are obviously limitations, but it’s an exciting idea.

We also use isotopes to tag genes in cells (Source), to track what fish are eating (This is called “isotopic labelling” – read more here), and even just to be able to see results better when we do tests on chemicals.

Conclusion

Isotopes rule. Do you agree?

Image Credits: Image of three hydrogen isotopes and single atom from Wikimedia Commons, image of Macklemore taken as a screenshot from his YouTube video, image of barrel from ruben96 on flickr, image of trout from Tresvalles Lodge

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