It has been claimed that man harnessed the power of the atom during the twentieth century. We developed nuclear weapons and used nuclear power to generate electricity. We’ve even broken the atom down into smaller pieces known as subatomic particles. Did you know when was the first time Atoms were precisely positioned on a flat surface?
In 1989, IBM scientists successfully arranged 35 individual xenon atoms on a chilled crystal of nickel substrate to spell out the initials “IBM.” It was the first time atoms were precisely placed on a flat surface.
What is an Atom?
An atom is a matter particle that uniquely defines a chemical element. An atom comprises a central nucleus surrounded by one or more electrons. Each electron carries a negative charge. The nucleus is positively charged and contains one or more relatively heavy protons and neutrons. (Source: Thought Co)
How Much Does an Atom Weight?
Avogadro stated that equal volumes of gases had the same number of molecules at the same temperature and pressure. So, he could calculate the atomic mass ratios by weighing the volumes of gases. A liter of oxygen, for example, weighed 16 times more than a liter of hydrogen, implying that an atom of oxygen must be 16 times the mass of a bit of hydrogen.
- Ammonia is formed by combining one liter of nitrogen with three liters of hydrogen (NH3)
- Hydrogen chloride is formed by combining one liter of hydrogen with one liter of chlorine (HCl)
This work produced a relative mass scale for elements in which all of the carbon-related details were included and chosen as the standard -12. Later experiments were able to describe the mass in grams of a substance to the number of atoms, and an atomic mass unit (amu) was discovered; 1 amu or Dalton is equal to 1.66 x 10-24 grams.
Chemists knew the atomic masses of elements and their chemical properties at the time, and a fantastic phenomenon jumped out at them. (Source: Thought Co)
The Atomic Theory
Atomic theory is a scientific theory that combines elements of physics, chemistry, and mathematics to describe the nature of atoms and matter. According to modern theory, matter is composed of tiny particles known as atoms, composed of subatomic particles. Atoms of a given element are similar in many ways but distinct from atoms of other elements. Atoms combine with other atoms in predetermined proportions to form molecules and compounds.
An atomic theory began as a philosophical concept in ancient India and Greece. The term atom is derived from the Greek word atomos, which means indivisible. Atomism holds that matter is made up of discrete particles. However, the theory was one of many possible explanations for matter and was not supported by empirical evidence.
Democritus proposed in the fifth century BCE that matter is made up of indestructible, indivisible units known as atoms. The Roman poet Lucretius recorded the idea, ensuring it survived the Dark Ages for future consideration. (Source: Thought Co)
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