Approximately how many atoms are in a mustard seed? Is it in the millions? Billions? Thousands?
Rough ball park figure- I’d guess about a qunitillion (10^18) give or take a few orders of magnitude.
Well if you assume that the average mustard seed is about .002 g and that the average atomic weight is about that of carbon, then I think it is avagadro’s number / 12 * .002.
Which will be about 10^20.
A lot more than billions.
What’s 100 quintillion or so among friends…
Right, more like a billion billion.
Wow, atoms must be really small
So does the term atomic weight signify that atoms can actually be weighed in some fashion and that some are heavier, some lighter? Does heavier mean they are bigger? Is it possible in theory that an element could exist with atoms the size of billiard balls? Planetoids? Are atoms real physical objects at all?
Apologies if I’m parading my ignorance here!
Yes.
Not if you consider the “size” to be equivalent to the atomic radius of the atom, that is, the extent of the electron cloud around the nucleus. Heavier atoms often have smaller atomic radii than lighter ones.
No.
Yes.
Basically, an atom is composed of three subatomic parts: The proton, neutron and electron. These are all forms of mass and make up matter which the more you have, the more gravity it produces, which… Well, I digress…
Generally, it’s the protons and neurons in the nucleus that make up most of the mass (and therefore its weight in a gravitational field). Hydrogen has one proton. Helium, two. Lithium, three, and so on. So the elements get successively heavier as you go down the periodic table.
The atoms are only bigger in that they have a larger cluster of protons and neutrons at their center (with the same number of electrons as protons, ignoring ions). Keep in mind these subatomic particles are crazy tiny. If the proton was the size of an apple, the much smaller electron would be “orbiting” a football field away. In between is empty space.
By a slightly different route:
If a mustard seed was pure allyl isocyanate (with an molecular weight of 99.15) ;
and an average mustard seed is 0.002 gm;
one mustard seed would have 2.017 x 10^-5 moles of allyl isocyanate.
By Avogadro’s constant there would be (6.023 *10^23 * 2.017 x 10^-5 = ) 1.34 X 10^19 molecules of allyl isocyanate. (quoting decimals in this calculation is meaningless)
There are 11 atoms (CH₂CHCH₂NCS) in a molecule of allyl isocyanate so IMHO **Folly’**s estimate of 10^20 atoms is pretty good.
Sure, if you realize that “empty space” is a shorthand concept for “a region of space where the probability of observing an electron is less than some predetermined value”, that electrons aren’t tiny little spheres, and that an electron’s ‘orbit’ is essentially nothing like a planet’s orbit.
For example, when an electron absorbs a photon and moves up to a higher orbit, it never occupies the space between the lower orbit and the higher one; its wavefunction changes in a tiny fraction of a second, during which time it has no well-defined position, and when the absorption interaction is complete, it’s in the new orbit. Similarly, when it emits a photon and jumps down to a lower orbit, it never occupies the space in between the lower orbit and the higher one. This is called a ‘quantum leap’.
We know this because we observe the universe has complex matter. If electrons could occupy any region of space around a nucleus they’re orbiting, they would spiral in, emitting hard radiation, and matter as we know it would be impossible. Instead, the lowest possible orbit is one that does not touch the nucleus and electrons never ‘spiral’ at all, in or out. (They may, however, absorb enough energy to leave the atom entirely, a process by which light can be converted to an electric charge or even an electric current. This is the photoelectric effect for which Einstein won his Nobel Prize.)