• Question: What is the atomic weight of silver?

    Asked by scientist.me.123 to Melissa, Angus on 15 Jun 2016.
    • Photo: Melissa Ladyman

      Melissa Ladyman answered on 15 Jun 2016:

      Atomic weight of silver: 107.87

      I had to look it up because I don’t do experiments with silver. But I do know the atomic weights for elements I work with all of the time. We use atomic weight to figure out how much of each chemical to put into our experiments so it’s really useful!

    • Photo: Angus Cook

      Angus Cook answered on 15 Jun 2016:

      As Melissa says, 107.87

      It’s a bit of a weird number. We don’t measure atomic weights using grams, because one gram of silver contains about 6,000,000,000,000,000,000,000 atoms of silver (that’s 6 and 21 zeroes afterwards). You can also say 6 sextillion. So if we had to use grams we’d have to say ‘one sextillionth of a gram’, it’s a bit of a mouthful.

      Instead we measure things in terms of the weight of other elements. You might think that we’d do it in terms of hydrogen (atomic mass of ~1) and say “silver is about 108 times the mass of hydrogen”, but instead we do it in terms of 1/12 of the mass of carbon (which has an atomic weight of 12, so 1/12 of 12 is 1… it can get a bit messy…).

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