202 amu

atomic mass

The basic unit of all matter is the atom. The atom is the smallest unit of matter that can’t be divided using any chemical means and the building block that has unique properties.

this number is called “avogadro’s number”, and it’s roughly 6.022 * 10^23. finally, each glucose molecule will have 6 + 10 + 5 = 21 atoms. so we just take (1 g/1 dollar)(1 mol/162 g)(6.022 * 10^23 molecules/mol)(21 atoms/molecule) = 7.806 * 10^22 atoms/dollar, which is around 78 sextillion atoms.

Democritus

Drawbacks of Dalton’s Atomic Theory The indivisibility of an atom was proved wrong: an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions. According to Dalton, the atoms of same element are similar in all respects.

Early History of the Atom Matter is composed of indivisible building blocks. This idea was recorded as early as the fifth century BCE by Leucippus and Democritus. The Greeks called these particles atomos, meaning indivisible, and the modern word “atom” is derived from this term.

As the universe continued to expand and cool, things began to happen more slowly. It took 380,000 years for electrons to be trapped in orbits around nuclei, forming the first atoms. These were mainly helium and hydrogen, which are still by far the most abundant elements in the universe.

Dalton’s theory has not proven to be correct under all circumstances. The first rule was proven incorrect when scientists divided atoms in a process called nuclear fission. The second rule was proven incorrect by the discovery that not all atoms of the same element have the same mass; there are different isotopes.

Dalton’s atomic theory was accepted by many scientists almost immediately. Most of it is still accepted today. However, scientists now know that atoms are not the smallest particles of matter. Atoms consist of several types of smaller particles, including protons, neutrons, and electrons.