Investigating Interesting Indium Information Quiz

Answer: From its indigo spectral lines

Indium was discovered by two German scientists, and its name has nothing to do with Indiana or India or any other place, nor was there a "Roberto Indio".

Different light has different wavelengths. Instead of traveling straightly, a light particle (or photon) travels up and down in curved crests as it moves forward, and the size of these crests is the wavelength. Different colors are the result of different wavelengths of light. Whenever an electron in an atom goes from a higher energy orbit around the nucleus of an atom to a lower energy orbit state (meaning the electron goes into an orbit closer to the middle of the atom), a photon is emitted. The wavelength of the photon depends on the atom (all atoms in a pure sample of an element are identical); that is to say, each element has different photon wavelengths from the orbit change of electrons, and thus different colors from these specific photons. These different colors are called spectral lines. Indium's is dominately indigo/blue and, at the time of its discovery, no other element had this spectral line "signature", leading those who saw it to conclude that it must come from an undiscovered element.

However, indium itself is silvery-white (like most elemental metals) and not indigo. That is because the color of indium that we see is caused by the wavelengths of the light bouncing off it, different from the spectral line photons that come from it.

Answer: Thallium

Indium's discoverers, Hieronymous Richter and Ferdinand Reich, were dissolving zinc compounds found in different ores to extract the zinc chloride from them. Thallium is sometimes found in these ores, and so they did a spectral line search to see if they could detect the spectral signature of thallium.

It was during this process that they detected the unique spectral lines from indium. They were able to extract the element a year later.

Answer: Softer than your fingernails

Indium is so soft you can easily scratch it with your fingernail or bend and mold it with your hands. It is one of the softest metals. Some other elements or compounds are as soft, like graphite, but are brittle and so won't mold like indium can.

Answer: Cadmium and tin

Elements on the periodic table are (for the most part) organized by their atomic numbers, which is the number of electrons that each atom of the element contains. Indium's atomic number is 49, and so can be found between the elements whose atomic numbers are 48 and 50, which are cadmium and tin respectively.

Answer: False

Nobody has ever died from indium poisoning, and there is no evidence to suggest indium can be directly harmful. Some indium compounds may be dangerous, but pure indium is safe.

Answer: In magnetic compass needles

Indium is not magnetic, and so is no used in magnetic compass needles. Indium tin oxide is used as an invisible conductor in LCDs such as those found in TVs and computers. Since indium can wet glass, it is used as a vacuum seal for gaskets in high-vacuum situations where rubber would be too porous.

There is also such a thing as indium leukocyte imaging, which can be used to watch what specific white blood cells do inside the body.

Answer: Ordinary metal

This group has a few other different names, such as "Poor metals" or "Post-transition metals".

Don't be fooled by the name: aluminum, tin and lead are also ordinary metals, but besides those three, the majority of the ordinary metals aren't what most people might consider "ordinary," such as thallium, gallium, bismuth or ununquadium.

Answer: Tin

However, when tin makes this sound, it is called a "tin cry". The tin cry is relatively well known, but the indium cry is less famous. Both are caused from crystals rearranging whilst bent.

Answer: 314°F or 157°C - considerably higher than the boiling point of water, but still quite low

The majority of metals have higher melting points than this. There are even bigger exceptions to this, most notably mercury, whose melting point is -38°F or -39°C.

Answer: Silvery-gray

Indium, like most metals on the periodic table, is silvery-gray in color in pure form. There are exceptions, such as gold, copper, and osmium.