Group 7 Infographic

This graphic looks at the halogens, found in Group 7 of the Periodic Table. This group consists of the elements fluorine, chlorine, bromine, iodine and astatine – the as yet unnamed artificial element 117, ununpentium, may also be a halogen. As always, the following are a few interesting nuggets of information too long to fit into the graphic itself.

Astatine was formerly considered to be the rarest element on Earth, but has been usurped in those stakes more recently by Berkelium, which can be produced in high concentration uranium deposits as a consequence of radioactive decay. It does still get to keep the title of being the rarest non-transuranic element, though (i.e., of all of the elements up to and including uranium). As a disclaimer, although the graphic states that astatine doesn’t form diatomic molecules, it’s more accurate to state that it’s yet to be proved one way or the other whether diatomic astatine actually exists.

As another disclaimer, the reactivity of the halogens decreasing down the group isn’t actually due to the fact that it gets harder to add an electron. However, this is the explanation peddled by most exam boards up to A Level in England, so despite it being a technically inaccurate explanation, it’s the one that makes it on to the graphic.

If more information on hydrofluoric acid is what you’re after, you can read The Chronicle Flask’s excellent post all about it and it’s associated hazards here. Long story short: really don’t spill it on yourself. It’s actually not as strong an acid as some more common acids, such as hydrochloric acid or sulphuric acid, but it’s fair to say it’s a good deal nastier.

As always you can download the high resolution pdf by clicking here. The infographics for the other groups in the periodic table can also be downloaded through the infographics section of the site.

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4 CommentsClose Comments


  • Kat
    Posted January 6, 2014 at 10:13 pm 0Likes

    Great post, and thanks for the mention! 🙂
    Being picky…. sorry can’t resist… pH is concentration dependent, so no acid has a fixed pH, despite what some pop science books may say (Sam Kean I’m looking at you 😉

    • Posted January 6, 2014 at 11:13 pm 0Likes

      No problem, thanks for the correction! Several weeks of teaching acids and bases to year 8s and persistently talking about pH has clearly got me into some bad habits 🙂 I’ve removed the pH references from the article to ensure it’s a little more factually accurate.

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