What is an Atom ?

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Here are 10 interesting and useful atom facts. There are three parts to an atom. Protons have a positive electrical charge and are found together with neutrons (no electrical charge) in the nucleus of each atom. Negatively charged electrons orbit the nucleus.

There are three parts to an atom. Protons have a positive electrical charge and are found together with neutrons (no electrical charge) in the nucleus of each atom. Negatively charged electrons orbit the nucleus.

Atoms are the smallest particles that make up elements. Each element contains a different number of protons. For example, all hydrogen atoms have 1 proton while all carbon atoms have 6 protons. Some matter consists of one type of atom (e.g., gold), while other matter is made of atoms bonded together to form compounds (e.g., sodium chloride).

Atoms are mostly empty space. The nucleus of an atom is extremely dense and contains nearly all of the mass of each atom. Electrons contribute very little mass to the atom (it takes 1836 electrons to equal the size of a proton) and orbit so far away from the nucleus that each atom is 99.9% empty space.

If the atom was the size of a sports arena, the nucleus would be the size of a pea. Although the nucleus is much denser compared with the rest of the atom, it too consists mainly of empty space.​

There are over 100 different kinds of atoms. About 92 of them occur naturally, while the remainder are made in labs. The first new atom made by man was technetium, which has 43 protons. New atoms can be made by adding more protons to an atomic nucleus. However, these new atoms (elements) are unstable and decay into smaller atoms instantaneously. Usually, we only know a new atom was created by identifying the smaller atoms from this decay.

The components of an atom are held together by three forces. Protons and neutrons are held together by the strong and weak nuclear forces. Electrical attraction holds electrons and protons. While electrical repulsion repels protons away from each other, the attracting nuclear force is much stronger than electrical repulsion.

The word "atom" comes from the Greek word for "uncuttable" or "undivided". The Greek Democritus believed matter consists of particles that could not be cut into smaller particles. For a long time, people believed atoms were the fundamental "uncuttable" unit of matter. While atoms are the building blocks of elements, that can be divided into still smaller particles. Also, nuclear fission and nuclear decay can break atoms into smaller atoms.

Atoms are very small. The average atom is about one-tenth of a billionth of a meter across. The largest atom (cesium) is approximately nine times bigger than the smallest atom (helium).

Although atoms are the smallest unit of an element, they consist of even tinier particles called quarks and leptons. An electron is a lepton. Protons and neutrons consist of three quarks each.

There are three parts to an atom. Protons have a positive electrical charge and are found together with neutrons (no electrical charge) in the nucleus of each atom. Negatively charged electrons orbit the nucleus.

The most abundant type of atom in the universe is the hydrogen atom. Nearly 74% of the atoms in the Milky Way galaxy are hydrogen atoms.

Atoms are the smallest particles that make up elements. Each element contains a different number of protons. For example, all hydrogen atoms have 1 proton while all carbon atoms have 6 protons.

You have around 7 billion billion billion atoms in your body, yet you replace about 98% of them every year!

Some matter consists of one type of atom (e.g., gold), while other matter is made of atoms bonded together to form compounds (e.g., sodium chloride).

An atom a fundamental piece of matter. (Matter is anything that can be touched physically.) Everything in the universe (except energy) is made of matter, and, so, everything in the universe is made of atoms.

Atoms are mostly empty space. The nucleus of an atom is extremely dense and contains nearly all of the mass of each atom. Electrons contribute very little mass to the atom (it takes 1836 electrons to equal the size of a proton) and orbit so far away from the nucleus that each atom is 99.9% empty space.

If the atom was the size of a sports arena, the nucleus would be the size of a pea. Although the nucleus is much denser compared with the rest of the atom, it too consists mainly of empty space.​

An atom itself is made up of three tiny kinds of particles called subatomic particles: protons, neutrons, and electrons. The protons and the neutrons make up the center of the atom called the nucleus and the electrons fly around above the nucleus in a small cloud. The electrons carry a negative charge and the protons carry a positive charge. In a normal (neutral) atom the number of protons and the number of electrons are equal. Often, but not always, the number of neutrons is the same, too.

The word “atom” comes from the ancient Greek word meaning ”undivided.” They thought that an atom couldn’t be cut into anything smaller, which we now know is not exactly right.

There are over 100 different kinds of atoms. About 92 of them occur naturally, while the remainder are made in labs. The first new atom made by man was technetium, which has 43 protons.

Atoms are mostly empty space and scientists think that there might be 200 or more subatomic particles. Some of them we already know about— neutrons, electrons, protons, quarks—but others are still waiting to be discovered.

What is an atom? Everything that takes up space called Matter (see States of Matter). Matter has weight, volume and mass. Matter is made up of tiny building blocks called Atoms. Atoms are tiny – at least 100 times smaller than the width of a human hair.

New atoms can be made by adding more protons to an atomic nucleus. However, these new atoms (elements) are unstable and decay into smaller atoms instantaneously. Usually, we only know a new atom was created by identifying the smaller atoms from this decay.