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WATCH FIRST

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Atoms are everything! Tim and Moby introduce you to atoms, which contain all the elements in the universe, and to the concepts of atomic number and atomic mass.

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Video

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What is an Atom -Basics for Kids - YouTube2

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In this interactive activity from ChemThink, learn about atomic structure.

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Atomic Structure

In this interactive activity from ChemThink, learn about atomic structure. Follow the tutorial to understand how individual atoms-the basis of all matter-are composed of subatomic particles such as electrons, protons, and neutrons. Investigate the three types of particles, their properties (such as mass and charge), and relative locations.

More simulations and resources are available on the SimBucket website.

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In this interactive activity from ChemThink, learn about atomic structure. Follow the tutorial to understand how individual atoms-the basis of all matter-are composed of subatomic particles such as electrons, protons, and neutrons. Investigate the three types of particles, their properties (such as mass and charge), and relative locations.

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Atoms are building blocks.

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Atoms are the foundation of chemistry. They are the basis for everything in the Universe. As you know, matter is composed of atoms. Solids are made of densely packed atoms while gases have atoms that are spread out. We're going to cover basics like atomic structure and bonding between atoms. As you learn more, you can move to the reactions and biochemistry pages and see how atoms form compounds that help the biological world survive.

Are there pieces of matter that are smaller than atoms? Sure there are. Super-small particles can be found inside the pieces of atoms. These subatomic particles include nucleons and quarks. Nuclear chemists and physicists work together at particle accelerators to discover the presence of these tiny, tiny, tiny pieces of matter. However, science is based on the atom because it is the smallest distinct unit of matter.

Even though many super-tiny atomic particles exist, you only need to remember the three basic parts of an atom: electrons, protons, and neutrons. What are electrons, protons, and neutrons? Electrons are the smallest of the three particles that make up atoms. Electrons are found in shells or orbitals that surround the nucleus of an atom. Protons and neutrons are found in the nucleus. They group together in the center of the atom. That's all you have to remember. Three easy pieces!

There are almost 120 known elements in the periodic table. (117 as we write this) Chemists and physicists are trying to make new ones every day in their labs. The atoms of different elements have different numbers of electrons, protons, and neutrons. Every element is unique and has an atomic number. That number tells you the number of protons in every atom of the element. The atomic number is also called the proton number.

You can see that each part of the atom is labeled with a "+", "-", or a "0." Those symbols refer to the charge of the particle. Have you ever heard about getting a shock from a socket, static electricity, or lightning? Those are all related to electric charges. Charges are also found in tiny particles of matter.

The electron always has a "-", or negative, charge. The proton always has a "+", or positive, charge. If the charge of an entire atom is "0", or neutral, there are equal numbers of positive and negative charges. Neutral atoms have equal numbers of electrons and protons. The third particle is the neutron. It has a neutral charge, also known as a charge of zero.

Since the number of protons in an atom does not change, fewer or extra electrons can create a special atom called an ion. Cations have fewer electrons and have a positive charge. Anions have extra electrons that create a negative charge.

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Chem4Kids.com! This tutorial introduces atomic structure in chemistry. Other sections include matter, elements, the periodic table, reactions, and biochemistry.

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Atoms and how they are related to elements, and the particles that make up atoms.

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Learn about the structure of the atom, and how atoms make up matter.

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Learn about the structure of the atom, and how atoms make up matter. An atom is the smallest unit of matter that retains all of the chemical properties of an element.

Introduction

What is your body made of? Your first thought might be that it is made up of different organs-such as your heart, lungs, and stomach-that work together to keep your body going. Or you might zoom in a level and say that your body is made up of many different types of cells. However, at the most basic level, your body-and, in fact, all of life, as well as the nonliving world-is made up of atoms, often organized into larger structures called molecules.

Atoms and molecules follow the rules of chemistry and physics, even when they're part of a complex, living, breathing being. If you learned in chemistry that some atoms tend to gain or lose electrons or form bonds with each other, those facts remain true even when the atoms or molecules are part of a living thing. In fact, simple interactions between atoms-played out many times and in many different combinations, in a single cell or a larger organism-are what make life possible. One could argue that everything you are, including your consciousness, is the byproduct of chemical and electrical interactions between a very, very large number of nonliving atoms!

So as an incredibly complex being made up of roughly 7,000,000,000,000,000,000,000,000,000 atoms, you'll probably want to know some basic chemistry as you begin to explore the world of biology, and the world in general.

Matter and elements

The term matter refers to anything that occupies space and has mass-in other words, the "stuff" that the universe is made of. All matter is made up of substances called elements, which have specific chemical and physical properties and cannot be broken down into other substances through ordinary chemical reactions. Gold, for instance, is an element, and so is carbon. There are 118 elements, but only 92 occur naturally. The remaining elements have only been made in laboratories and are unstable.

Each element is designated by its chemical symbol, which is a single capital letter or, when the first letter is already "taken" by another element, a combination of two letters. Some elements follow the English term for the element, such as C for carbon and Ca for calcium. Other elements' chemical symbols come from their Latin names; for example, the symbol for sodium is Na, which is a short form of natrium, the Latin word for sodium.

The four elements common to all living organisms are oxygen (O), carbon (C), hydrogen (H), and nitrogen (N), which together make up about 96% of the human body. In the nonliving world, elements are found in different proportions, and some elements common to living organisms are relatively rare on the earth as a whole. All elements and the chemical reactions between them obey the same chemical and physical laws, regardless of whether they are a part of the living or nonliving world.

The structure of the atom

An atom is the smallest unit of matter that retains all of the chemical properties of an element. For example, a gold coin is simply a very large number of gold atoms molded into the shape of a coin, with small amounts of other, contaminating elements. Gold atoms cannot be broken down into anything smaller while still retaining the properties of gold. A gold atom gets its properties from the tiny subatomic particles it's made up of.

An atom consists of two regions. The first is the tiny atomic nucleus, which is in the center of the atom and contains positively charged particles called protons and neutral, uncharged, particles called neutrons. The second, much larger, region of the atom is a "cloud" of electrons, negatively charged particles that orbit around the nucleus. The attraction between the positively charged protons and negatively charged electrons holds the atom together. Most atoms contain all three of these types of subatomic particles -protons, electrons, and neutrons. Hydrogen (H) is an exception because it typically has one proton and one electron, but no neutrons. The number of protons in the nucleus determines which element an atom is, while the number of electrons surrounding the nucleus determines which kind of reactions the atom will undergo. The three types of subatomic particles are illustrated below for an atom of helium-which, by definition, contains two protons.

Protons and neutrons do not have the same charge, but they do have approximately the same mass, about grams. Since grams are not a very convenient unit for measuring masses that tiny, scientists chose to define an alternative measure, the dalton or atomic mass unit (amu). A single neutron or proton has a weight very close to 1 amu. Electrons are much smaller in mass than protons, only about 1/1800 of an atomic mass unit, so they do not contribute much to an element's overall atomic mass. On the other hand, electrons do greatly affect an atom's charge, as each electron has a negative charge equal to the positive charge of a proton. In uncharged, neutral atoms, the number of electrons orbiting the nucleus is equal to the number of protons inside the nucleus. The positive and negative charges cancel out, leading to an atom with no net charge.

Protons, neutrons, and electrons are very small, and most of the volume of an atom-greater than 99 percent-is actually empty space. With all this empty space, you might ask why so-called solid objects don't just pass through one another. The answer is that the negatively charged electron clouds of the atoms will repel each other if they get too close together, resulting in our perception of solidity.

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Matter, elements, and atoms | Chemistry of life (article) | Khan Academy

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Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.

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Atoms Tour

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What are atoms? A very basic overview of atomic structure.

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Labeling an Atom

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Interactive Whiteboard educational quizzes and flash games for the school classroom

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Atoms Facts

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Atoms Facts

The name atom comes from the Greek word atomos, which means uncuttable; this implies that atoms are the smallest unit and are not dividable. They are often described as the basic unit of matter.

Atoms contain a dense nucleus surrounded by a cloud of electrons, which contain a negative charge.

The interior of the nucleus contains positively charged protons, and almost all atoms' nuclei (with the exception of hydrogen-1) contain neutrally charged neutrons.

Nearly one hundred percent of the mass of an atom (99.94%) is contained in the nucleus.

The mass of the protons and the mass of the neutrons are almost the same.

Electromagnetic force binds the electron cloud to the nucleus.

A nearly identical force can allow atoms to bind together, forming molecules.

Atoms exist as either electrically neutral, or ions.

In an electrically neutral atom, the number of protons equals the number of electrons, thus cancelling each other out.

In an ion, however, there are more of one of particle than the other, making the atom have either a positive or negative charge.

Atoms are classified according to their numbers of protons or neutrons.

The number of protons in the atom will determine its chemical element, and the number of neutrons will determine its isotope.

Every element has at least one isotope, and many elements have multiple isotopes.

The isotopes undergo radioactive decay due to their unstable nuclei.

The scientific field of quantum mechanics has led to a successful model of the atom and its observable properties.

It wasn't until the end of the 19th century and beginning of the 20th century that scientists began to discover subatomic particles contained within the atom.

As researchers discovered the existence and properties of subatomic particles, a debate ensued about the fact that there was actually something smaller than an atom and that atoms could be divided, nullifying its name.

Some proponents wanted to change the name of the atom to reflect this new understanding, but it didn't catch on.

The first understandings of the existence of atoms date back to ancient Greece, and it was Democritus who first used the term "atomos" (atom).

Early scientists in ancient India independently developed theories on the existence of atoms.

In 1661, Robert Boyle first published the theory that all matter was composed of atoms.

The nature and structure of atoms was improved upon beginning in the 18th century with the advances in chemistry.

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Atoms Facts The name atom comes from the Greek word atomos, which means uncuttable; this implies that atoms are the smallest unit and are not dividable. They are often described as the basic unit of matter. Atoms contain a dense nucleus surrounded by a cloud of electrons, which contain a negative charge.