Another chemistry Christmas logic puzzle

For a North American Christmas party, three Christmas trees are decorated — one for each of the largest countries: Mexico, United States and Canada. Each tree is designed with ten hexagonal shapes — pictured below. Each hexagon contains a different elemental symbol. In all cases if you add the atomic numbers of the 10 elements, you will get the same number, 207.

Three trees with hexagonal leaves, labelled Mexican tree, American tree and Canadian tree.

In this puzzle your task is to find the 10 elements present on each tree and their position on the tree.

To help you, here are some hints:

  1. For all the elements included in this puzzle, the highest atomic number is 54 and the lowest is 2. As well, there is at least one element from every group in the periodic table. In no case are there two elements from the same group on one tree.
  2. Six test tubes each with coloured substances.Every tree contains a noble gas in the top red space and an alkaline-earth metal in the bottom white space. Neon is on the Mexican tree. An element essential for the maintenance of healthy teeth, nails and bones is on the American tree.
  3. Only the Mexican and the American trees contain a halogen in the middle green space. Only the American and the Canadian trees contain an element from group 4 in the top white space.
  4. Three elements present in the chlorophyll molecule are in the three white spaces on the Mexican tree.
  5. Fluorine, scandium and niobium are all on different trees. On the contrary, sodium, boron and helium are on the same one.
  6. In the three green spaces of the Canadian tree you will find the element that constitutes around 21% of our atmosphere, the element discovered in 1774 by Johan Gottlieb Gahn, and the element discovered in 1751 by Axel Cronstedt — both Swedish mineralogists.
  7.  Although not on its tree, Mexico is one of the top producers of this precious metal, which you will find in a red space on the same tree where arsenic is placed just below helium.
  8.  The primary element present in bronze is in a red space on the Canadian tree, just below lithium.
  9.  In the green spaces of the Mexican tree you will find two metals known since ancient times. In the middle of this same tree, the red hexagon contains the transition element present in vitamin B12.
  10. In the American tree, the bottom red space has an element present in table salt, just below the element named after the Greek word for color.
  11. Aluminum, gallium and sulfur are placed in the bottom right red space on the trees.
  12. Only one group 3 element is present on the Canadian tree just below an element found in mineral ores such as ilmenite, anatase and rutile.
  13. A metal element with a low melting point — it could melt in your hand — is on the Mexican tree, below an element associated with the purification and disinfection of water.
  14. On the occasion when two or more elements could occupy two or more spaces in the same tree, and there are no other hints to help you decide, place the one with the lower atomic number in a lower position. Make sure that all the other clues have been satisfied first.

The periodic table above can help you track the elements used in this puzzle to ensure there is one element from every group. It will also provide the atomic numbers.

Want a printable PDF of this puzzle, email Jean Hein.

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