Atom

Atom

 An atom is the smallest possible piece of a chemical element. All matter is made of groups of atoms bonded, or connected, together into molecules.

The word atom comes from the Greek word “atomos,” which means “indivisible.”  Scientists used to think that atoms could not be broken up into smaller parts. But today, we know that they can. Atoms are made of smaller parts — protons, electrons and neutrons. Protons are particles with a tiny positive electrical charge. Neutrons have no electrical charge. And electrons have a tiny negative charge.

In an atom, the protons and neutrons hang out in the center, or nucleus. The electrons travel in a cloud around the nucleus. The cloud is split into layers called orbitals, where electrons are likely to be. Atoms of different elements have different numbers of protons, neutrons and electrons. The number of protons an atom has (its atomic number) determines which element it is.

The combination of protons, neutrons and electrons in an atom give each element its unique properties. For example, the four electrons in carbon’s outermost layer give this atom the ability to bond with up to four other atoms. This makes carbon an essential building block for every living thing on Earth. The 226 neutrons in radium-226 make this atom glow in the dark.

Because they are made of smaller particles, atoms can be broken up into pieces. Once that happens, though, the pieces are no longer a part of one chemical element. Break up a carbon atom, and you no longer have carbon. So a carbon atom is still the smallest possible piece of carbon.

Power words

atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.

atomic: Having to do with atoms, the smallest possible unit that makes up a chemical element.

atomic number: The number of protons in an atomic nucleus, which determines the type of atom and how it behaves.

bond: (in chemistry) A semi-permanent attachment between atoms — or groups of atoms — in a molecule. It’s formed by an attractive force between the participating atoms. Once bonded, the atoms will work as a unit. To separate the component atoms, energy must be supplied to the molecule as heat or some other type of radiation.

carbon: The chemical element having the atomic number 6. It is the physical basis of all life on Earth. Carbon exists freely as graphite and diamond. It is an important part of coal, limestone and petroleum, and is capable of self-bonding, chemically, to form an enormous number of chemically, biologically and commercially important molecules. (in climate studies) The term carbon sometimes will be used almost interchangeably with carbon dioxide to connote the potential impacts that some action, product, policy or process may have on long-term atmospheric warming.

chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

electron: A negatively charged particle, usually found orbiting the outer regions of an atom; also, the carrier of electricity within solids.

element: A building block of some larger structure. (in chemistry) Each of more than one hundred substances for which the smallest unit of each is a single atom. Examples include hydrogen, oxygen, carbon, lithium and uranium.

matter: Something that occupies space and has mass. Anything on Earth with matter will have a property described as "weight."

molecule: An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).

neutron: A subatomic particle carrying no electric charge that is one of the basic pieces of matter. Neutrons belong to the family of particles known as hadrons.

nucleus: Plural is nuclei. (in biology) A dense structure present in many cells. Typically a single rounded structure encased within a membrane, the nucleus contains the genetic information. (in astronomy) The rocky body of a comet, sometimes carrying a jacket of ice or frozen gases. (in physics) The central core of an atom, containing most of its mass.

orbital: Adjective for something relating to orbits. (in chemistry and subatomic physics) The pattern(s) of electrons (and their density) that form(s) within an atom or molecule.

particle: A minute amount of something.

proton: A subatomic particle that is one of the basic building blocks of the atoms that make up matter. Protons belong to the family of particles known as hadrons.

 

Let’s learn about colors

We live in a colorful world. Green leaves spring from the trees, flowers come in every color of the rainbow, and birds sport fashionably colorful feathers. We even live on a pale blue dot.

What creates all this color? Electromagnetic radiation — waves of energy moving through space. The waves come in different lengths. Cells in the backs of our eyes can perceive light as black, white, red, green or blue. The cells then relay that information to the brain — and we see the world in color. But we don’t see every color. Many wavelengths are beyond what humans can see.Nature has come up with many ways to make colors. Leaves, for instance, get their green from chlorophyll — the same chemical that helps them make sugar from sunlight. Some beetles, though, are beautifully shimmery from tiny structures in their wings. Those structures bounce light off differently at each angle, producing iridescence. And peacock spiders use a combination of pigments and tiny structures to get their beautiful behinds.

Power words

angle: The space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.

beetle: An order of insects known as Coleoptera, containing at least 350,000 different species. Adults tend to have hard and/or horn-like “forewings” which covers the wings used for flight.

birds: Warm-blooded animals with wings that first showed up during the time of the dinosaurs. Birds are jacketed in feathers and produce young from the eggs they deposit in some sort of nest. Most birds fly, but throughout history there have been the occasional species that don’t.

cell: The smallest structural and functional unit of an organism. Typically too small to see with the unaided eye, it consists of a watery fluid surrounded by a membrane or wall. Depending on their size, animals are made of anywhere from thousands to trillions of cells. Most organisms, such as yeasts, molds, bacteria and some algae, are composed of only one cell.

chemical: A substance formed from two or more atoms that unite (bond) in a fixed proportion and structure. For example, water is a chemical made when two hydrogen atoms bond to one oxygen atom. Its chemical formula is H2O. Chemical also can be an adjective to describe properties of materials that are the result of various reactions between different compounds.

chlorophyll: Any of several green pigments found in plants that perform photosynthesis — creating sugars (foods) from carbon dioxide and water.

electromagnetic: An adjective referring to light radiation, to magnetism or to both.

electromagnetic radiation: Energy that travels as a wave, including forms of light. Electromagnetic radiation is typically classified by its wavelength. The spectrum of electromagnetic radiation ranges from radio waves to gamma rays. It also includes microwaves and visible light.

hue: A color or shade of some color.

iridescent: Adjective that describes something that seems to change color with a shift in the angle at which it is viewed or at which lighting is applied.

pigment: A material, like the natural colorings in skin, that alter the light reflected off of an object or transmitted through it. The overall color of a pigment typically depends on which wavelengths of visible light it absorbs and which ones it reflects. For example, a red pigment tends to reflect red wavelengths of light very well and typically absorbs other colors. Pigment also is the term for chemicals that manufacturers use to tint paint.

radiant: (adj.) A term for something that is radiated, such as heat or some other type of radiation. (n.) The point or object from which light or heat radiates (such as the heating element in an electric heater). Or the point from which objects (such as meteors) appear to come.

radiation: (in physics) One of the three major ways that energy is transferred. (The other two are conduction and convection.) In radiation, electromagnetic waves carry energy from one place to another. Unlike conduction and convection, which need material to help transfer the energy, radiation can transfer energy across empty space.

robot: A machine that can sense its environment, process information and respond with specific actions. Some robots can act without any human input, while others are guided by a human.

spider: A type of arthropod with four pairs of legs that usually spin threads of silk that they can use to create webs or other structures.

wave: A disturbance or variation that travels through space and matter in a regular, oscillating fashion.

wavelength: The distance between one peak and the next in a series of waves, or the distance between one trough and the next. It’s also one of the “yardsticks” used to measure radiation. Visible light — which, like all electromagnetic radiation, travels in waves — includes wavelengths between about 380 nanometers (violet) and about 740 nanometers (red). Radiation with wavelengths shorter than visible light includes gamma rays, X-rays and ultraviolet light. Longer-wavelength radiation includes infrared light, microwaves and radio waves.

Electron

 Electron

This is one of the three types of particles that make up an atom. The other two are protons and neutrons. Protons and neutrons form the center, or nucleus, of an atom. Electrons exist in a surrounding cloud. They swarm around the center of the atom. That’s because electrons have negative electric charge. That makes them attracted to the positively charged protons in the nucleus. Normally, atoms have the same number of electrons as protons. So the atoms are electrically neutral.

Unlike protons and neutrons, electrons don’t contain smaller particles. That is, they are fundamental particles. Each electron is extremely small. Its mass is only about 1/1,800 the mass of a proton or neutron. Still, electrons play an important role in how atoms behave. Atoms of different elements hold their electrons in different arrangements around the nucleus. That arrangement gives each element its distinct properties. For instance, it determines how well an element conducts electricity. It also determines the temperature at which the element boils. And, that arrangement governs how likely atoms are to share electrons with each other. When atoms share electrons, they link together and form molecules.

Power words

atom: The basic unit of a chemical element. Atoms are made up of a dense nucleus that contains positively charged protons and uncharged neutrons. The nucleus is orbited by a cloud of negatively charged electrons.

cloud: A plume of molecules or particles, such as water droplets, that move under the action of an outside force, such as wind, radiation or water currents. 

electric charge: The physical property responsible for electric force; it can be negative or positive.

electron: A negatively charged particle, usually found orbiting the outer regions of an atom; also, the carrier of electricity within solids.

fundamental: Something that is basic or serves as the foundation for another thing or idea.

ion: (adj. ionized) An atom or molecule with an electric charge due to the loss or gain of one or more electrons. An ionized gas, or plasma, is where all of the electrons have been separated from their parent atoms.

link: A connection between two people or things.

mass: A number that shows how much an object resists speeding up and slowing down — basically a measure of how much matter that object is made from.

matter: Something that occupies space and has mass. Anything on Earth with matter will have a property described as "weight."

molecule: An electrically neutral group of atoms that represents the smallest possible amount of a chemical compound. Molecules can be made of single types of atoms or of different types. For example, the oxygen in the air is made of two oxygen atoms (O2), but water is made of two hydrogen atoms and one oxygen atom (H2O).

neutron: A subatomic particle carrying no electric charge that is one of the basic pieces of matter. Neutrons belong to the family of particles known as hadrons.

nucleus: Plural is nuclei. (in physics) The central core of an atom, containing most of its mass.

particle: A minute amount of something.

plasma: (in chemistry and physics) A gaseous state of matter in which electrons separate from the atom. A plasma includes both positively and negatively charged particles.

proton: A subatomic particle that is one of the basic building blocks of the atoms that make up matter. Protons belong to the family of particles known as hadrons.