The Atom The atom is one of the basic units of matter. Everything around us is made up of atoms. An atom is incredibly tiny -more than a million times smaller than the thickness of a human hair. The smallest speck that can be seen under an ordinary microscope contains more than 10 billion atoms. The diameter of an atom ranges from about 0.1 to 0.5 nanometer. Atoms form the building blocks of the simplest substances, the chemical …
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showed last 75 words of 3702 total
…a chemical element that forms 0.94 percent of the earth's atmosphere. Most ordinary light bulbs are filled with argon and a little nitrogen. Argon is also used as a shielding gas in arc welding to protect the metal from oxygen in the air. Lord Rayleigh and Sir William Ramsay discovered it in 1894. Argon is a colorless, odorless, tasteless gas. It does not react readily with other chemicals. This chemical element is classed as a noble gas