Chemistry Analysis

Develop a passion for learning

Atom in chemistry

Atoms are the basic units of matter and the specific structure of elements. The term “atom” comes from the Greek word “indivisible”, meaning “indivisible,” because the Greeks at the time believed that the atom is the smallest thing in the universe and indivisible. But now we know that atoms are made up of three types of particles: protons, neutrons, and electrons, and we know that they are also made up of smaller particles like quarks.


Atoms formed after the Big Bang, 13.7 billion years ago. When the hot and dense universe began to expand, it became cooler, and then the conditions allowed quarks and electrons to form. The quarks are clustered together to form protons and neutrons, and these particles are incorporated into the nucleus. All this happened during the first few minutes of the universe, according to CERN.

It took the universe 380,000 years to cool down enough to slow the electrons so the nuclei could pick them up to form the first atoms. The first atoms were hydrogen and helium, which are still the most abundant elements in the universe. Gravity then began to control the clouds of gas to form stars, which in turn formed heavier atoms (and this process continues to this day) and when the star’s death explodes in a massive event called (Supernova), spreading its precious content throughout the universe.

An atom is the smallest unit of matter, containing all the chemical elements of an element. An atom consists of a nucleus of protons charged with a positive charge, moderately charged neutrons, and negatively charged electrons, all orbiting the nucleus. The protons and neutrons that makeup them, and whether they contain electrons, have a typical atom size of about 0.1 nanometers, and most of them are empty space, where the electrons are located, and usually small atoms are similar in shape, so they are spherical.

atom Ingredients

The atom is made up of two regions, the small atomic nucleus, the center of the atom, which contains protons and neutrons, and an area that forms a cloud of electrons orbiting the nucleus, which is much larger than the atom. Most of the atoms contain these three particles, except hydrogen. One electron and no neutrons.

The basic types of an atom

Atomic number

The atomic number refers to the number of positively charged units, the protons in the nucleus. The neutral atom contains an equal number of protons and electrons, so that the positive and negative charges are balanced together, and the number of protons in the nucleus determines the chemical properties of the atom. , While electrons determine how an atom interacts with other atoms.

Atomic mass and isotopes

The number of neutrons in the nucleus affects the mass of an atom and does not affect its chemical properties. If the nucleus contains six protons and six neutrons, it is an atom similar to its properties with an atom that contains six protons and eight neutrons, but they differ in their mass, It is believed that nuclei that contain the same number of protons, but differ in the number of neutrons, are isotopes of each other, and all chemical elements of many isotopes.

Atomic molecules

Protons and neutrons are heavier than electrons and settle into the nucleus that is the center of an atom. The electrons are extremely lightweight and are found in a cloud orbiting the nucleus. The electron cloud radius is 10,000 times the diameter of the nucleus.

Protons and neutrons have roughly the same mass. But a single proton weighs more than 1,800 electrons. Atoms always have an equal number of protons and electrons, and the number of protons and neutrons is usually the same. Adding a proton to the nucleus produces a new, less-weight element, which stars do while adding a neutron produces an isotope or a heavier version of that element.

The nucleus of the atom

The nucleus was discovered in 1911 by New Zealand physicist Rutherford, who proposed in 1920 to name the proton positively charged molecules in the nucleus. Rutherford theorized that there was a neutral particle inside the nucleus, and his student James Chadwick, a British physicist, was able to confirm this in 1932.

Almost every mass of an atom is in its nucleus. Protons and neutrons have roughly the same mass as the “slightly less proton” and have the same angular momentum, according to Lawrence Berkeley National Laboratory.

The components of the nucleus are joined together by “strong nuclear force”, one of the four fundamental forces in nature. This force between protons and neutrons overcomes the electrical repulsion force, which, according to the rules of electricity, would keep protons apart. Some atomic nuclei are unstable because the binding forces vary depending on the size of the nucleus. These atoms then decompose into other elements, such as the decomposition of carbon 14 to nitrogen 14.


Protons are positively charged molecules found inside the nucleus of an atom. Rutherford discovered it in his experiments on cathode ray tubes he conducted between 1911 and 1919. Protons are less mass than neutrons. They have a relative mass = 0.9986 (compared to a neutron mass = 1) or about 1.673 × 10-27 kg.

The number of protons in an atom determines the type of element; for example, a carbon atom has 6 protons, hydrogen 1, and oxygen 8. The number of protons in an atom is called the element’s atomic number, and the number of protons also determines the chemical behavior of the element. The periodic table ranks the elements according to their atomic number.

Each proton consists of 3 quarks – two up quarks (each with a positive charge of ⅔) and a quark down (with a negative charge of ⅓) – which are collected together by other subatomic particles called gluons, which are massless.

Electrons in an atom

The electron is small compared to protons and neutrons, it is more than 1800 times smaller. If we consider that the mass of the neutron = 1, the relative mass of the electron = 0.0005439, or about 9.109 × 10-31 kg.

The British physicist Thompson discovered the electron in 1887, originally known as “Corpuscles,” which are pellets, negatively charged electrons and electrically attracted to positively charged protons. Electrons surround the nucleus in pathways called orbits, an idea put forward by Austrian physicist Schrödinger in the 1920s. This model is known today as the quantum model or the cloud model. The inner orbits near the nucleus are spherical and the outer orbits are much more complex.

Electron distribution is the orbital description of the locations of electrons in a typical atom. Using electronic distribution and physics principles, chemists can predict the properties of an atom. Such as stability, boiling point, and conduction.

You may also like:

What is the theory of relativity

%d bloggers like this: