What and Where are Atoms?

Source: Live Science

Atoms are the basic units of matter and the defining structure of elements as mentioned in most Physics classes. The term “atom” is derived from the Greek word invisible, makes sense doesn’t it? At one point in history atoms were considered to be the smallest matter in the universe and thus assumed could not be divided. Again, of you’d paid attention to your Physics lesson you’d be know that atoms consist of Protons, Neutrons and Electrons, which by the are composed of even smaller particles called quarks.

Thought to have been created 13.7 billion years ago after the Big Bang and no, we aren’t referring to “The Big Bang Theory”, which airs on CBS. The occurrence came about as the hot, dense new universe cooled, conditions became suitable for quarks and electrons to form. These quarks again came together to form protons and neutrons which in turn upon combination created nuclei. This all took place within the first few minutes of the universe’s existence, according to CERN.

Scientists believe the universe took nearly 380,000 years to cool down enough to slow the electrons subsequently enabling the nuclei capture them to form the first atoms. The earliest atoms were primarily hydrogen and helium, which are still the most abundant elements in the universe, according to Jefferson Lab Gravity eventually caused clouds of gas to coalesce and form stars, and heavier atoms were (and still are) created within the stars and sent throughout the universe when the star exploded (supernova).

Atomic particles

Generally, we know that protons and neutrons are heavier than electrons and reside in the nucleus at the centre of the atom. The lightest of the two, electrons exist in a cloud orbiting the nucleus. The electron cloud has a radius 10,000 times greater than the nucleus, according to the Los Alamos National Laboratory.

Both protons and neutrons have the same mass although on paper one proton is a

Is about 1,835 times larger than an electron. Atoms have the same number of electrons and protons and the number of protons and neutrons are the same as well. When a proton is added to an atom it makes a new element whereas when a neutron is added an isotope or a heavier version of the atom is made.

Nucleus

Discovered in 1911 by Ernest Rutherford, a physicist from New Zealand. In 1920, Rutherford proposed the name proton for the positively charged particles of the atom. He also theory on the neutral particle with the nucleus was later confirmed in 1932, by British physicist James Chadwick

According to Chemistry LibreText the mass of the atom resides in the nucleus. Protons and neutrons that make up the nucleus are the same mass and have the same angular movement

The strong force, one of the four basic forces of nature is what holds the nucleus together This force between the protons and neutrons overcomes the repulsive electrical force that would otherwise push the protons apart, according to the rules of electricity.

Varying binding forces, which have unstable atomic nuclei vary for different atoms based on the size of the nucleus. Such as carbon-14 decaying into nitrogen-14.

Protons

Positively charged particles found within atomic nuclei discovered by Rutherford while conducting experiments with cathode-ray tubes. Protons are about 99.86% as large as neutrons.

The number of protons in an atom is unique meaning a carbon atom may have six protons and oxygen atoms may have eight atoms while a hydrogen atom would have one.

If you recall your physics lesson then you’d know that the proton number of an atom is referred to as the atomic number of that element. The chemical behaviour of that element is also determined by the number of protons of that element. Elements are arranged according to the Periodic Table in order of increasing atomic number.

Three quarks make up each proton — two “up” quarks (each with a two-thirds positive charge) and one “down” quark (with a one-third negative charge) — and they are held together by other subatomic particles called gluons, which are massless.

Electrons

Electrons are 1,800 times smaller than protons or neutrons and are about 0.054% as massive as neutrons, according to Jefferson Lab.

The electron was discovered by British physicist, Joseph John Thomson in 1897. Originally known as “corpuscles” electrons are negatively charged and are electrically attached to the positively charged protons. Electrons surround the atomic nucleus in pathways called orbitals, a term coined by Erwin Schrödinger, an Austrian physicist, in the 1920s. At present, however, the model is known as the quantum model or the electron cloud model.

The inner orbitals surrounding the atom are spherical but the outer orbitals are much more complicated.

The electron configuration of an atom refers to the location of the electrons in an atom. Using the electron configuration and principles of physics, chemists can predict an atom’s properties, such as stability, boiling point and conductivity.

Neutrons

The neutron’s existence was theorized by Rutherford in 1920 and discovered by Chadwick in 1932 and were found during experiments when atoms were shot at a thin sheet of beryllium. Neutrons are uncharged particles found within all atomic nuclei (except for hydrogen).

The mass of a neutron is slightly larger than that of a proton and like protons, neutrons are also made of quarks. One “up” quark (with a positive 2/3 charge) and two “down” quarks (each with a negative one-third charge).