What is atoms

Atoms were created after the Big Bang As the hot, dense new universe cooled, conditions became suitable for quarks and electrons to form.

Quarks came together to form protons and neutrons, and these particles combined into nuclei. This all took place within the first few minutes of the universe's existence, according to CERN. It took , years for the universe to cool enough to slow down the electrons so that the nuclei could 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. Protons and neutrons are heavier than electrons and reside in the nucleus at the center of the atom. Electrons are extremely lightweight and exist in a cloud orbiting the nucleus. The electron cloud has a radius 10, times greater than the nucleus, according to the Los Alamos National Laboratory.

Protons and neutrons have approximately the same mass. However, one proton is about 1, times more massive than an electron. Atoms always have an equal number of protons and electrons, and the number of protons and neutrons is usually the same as well. Adding a proton to an atom makes a new element, while adding a neutron makes an isotope, or heavier version, of that atom. The nucleus was discovered in by Ernest Rutherford, a physicist from New Zealand. In , Rutherford proposed the name proton for the positively charged particles of the atom.

He also theorized that there was a neutral particle within the nucleus, which James Chadwick, a British physicist and student of Rutherford's, was able to confirm in Virtually all the mass of an atom resides in its nucleus, according to Chemistry LibreTexts. The protons and neutrons that make up the nucleus are approximately the same mass the proton is slightly less and have the same angular momentum, or spin.

The nucleus is held together by the strong force , one of the four basic forces in nature. 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.

Some atomic nuclei are unstable because the binding force varies for different atoms based on the size of the nucleus. These atoms will then decay into other elements, such as carbon decaying into nitrogen Protons are positively charged particles found within atomic nuclei.

Rutherford discovered them in experiments with cathode-ray tubes that were conducted between and Protons are about The number of protons in an atom is unique to each element.

For example, carbon atoms have six protons, hydrogen atoms have one and oxygen atoms have eight. The number of protons in an atom is referred to as the atomic number of that element.

The number of protons also determines the chemical behavior of the element. Elements are arranged in the Periodic Table of the Elements 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 are tiny compared to protons and neutrons, over 1, times smaller than either a proton or a neutron.

Electrons are about 0. Joseph John J. Thomson, a British physicist, discovered the electron in , according to the Science History Institute. Originally known as "corpuscles," electrons have a negative charge and are electrically attracted to the positively charged protons.

The smallest atom , when she chooses to make use of it, is obliged to obey her will. A unit of matter ; the smallest unit of a chemical element. Each atom consists of a nucleus , which has a positive charge , and a set of electrons that move around the nucleus. See Bohr atom. New Word List Word List.

Save This Word! See synonyms for atom on Thesaurus. We could talk until we're blue in the face about this quiz on words for the color "blue," but we think you should take the quiz and find out if you're a whiz at these colorful terms.

Words nearby atom at. Words related to atom bit , crumb , dot , fragment , grain , iota , jot , minimum , mite , modicum , molecule , morsel , mote , ounce , particle , scintilla , scrap , shred , smidgen , speck. Matthew R. Uncanny Tales Various. The Cromptons Mary J. The Elements of Qualitative Chemical Analysis, vol.

Julius Stieglitz. Buffon's Natural History. A unit of matter, the smallest unit of an element, having all the characteristics of that element and consisting of a dense, central, positively charged nucleus surrounded by a system of electrons. The entire structure has an approximate diameter of 10 -8 centimeter and characteristically remains undivided in chemical reactions except for limited removal, transfer, or exchange of certain electrons. This unit regarded as a source of nuclear energy.

A part or particle considered to be an irreducible constituent of a specified system.