Atom what is it

That's what keeps the atom together. How could something as small as an atom move a space craft? What is a propellant? How are atoms charged? How do you make an ion? Originally known as "corpuscles," electrons have a negative charge and are electrically attracted to the positively charged protons. Today, this model is known as the quantum model or the electron cloud model. The inner orbitals surrounding the atom are spherical but the outer orbitals are much more complicated.

An atom's electron configuration refers to the locations of the electrons in a typical atom. Using the electron configuration and principles of physics, chemists can predict an atom's properties, such as stability, boiling point and conductivity, according to the Los Alamos National Laboratory.

The neutron's existence was theorized by Rutherford in and discovered by Chadwick in , according to the American Physical Society. Neutrons were found during experiments when atoms were shot at a thin sheet of beryllium.

Subatomic particles with no charge were released — the neutron. Neutrons are uncharged particles found within all atomic nuclei except for hydrogen. A neutron's mass is slightly larger than that of a proton. The theory of the atom dates at least as far back as B. Democritus most likely built his theory of atoms upon the work of past philosophers, according to Andrew G. Democritus' explanation of the atom begins with a stone.

A stone cut in half gives two halves of the same stone. If the stone were to be continuously cut, at some point there would exist a piece of the stone small enough that it could no longer be cut. The term "atom" comes from the Greek word for indivisible, which Democritus concluded must be the point at which a being any form of matter cannot be divided any more. His explanation included the ideas that atoms exist separately from each other, that there are an infinite amount of atoms, that atoms are able to move, that they can combine together to create matter but do not merge to become a new atom, and that they cannot be divided, according to Universe Today.

However, because most philosophers at the time — especially the very influential Aristotle — believed that all matter was created from earth, air, fire and water, Democritus' atomic theory was put aside.

John Dalton, a British chemist, built upon Democritus' ideas in when he put forth his own atomic theory, according to the chemistry department at Purdue University. Dalton's theory included several ideas from Democritus, such as atoms are indivisible and indestructible and that different atoms form together to create all matter.

Dalton's additions to the theory included the following ideas: That all atoms of a certain element were identical, that atoms of one element will have different weights and properties than atoms of another element, that atoms cannot be created or destroyed and that matter is formed by atoms combining in simple whole numbers.

Thomson, the British physicist who discovered the electron in , proved that atoms can be divided, according to the Chemical Heritage Foundation. He was able to determine the existence of electrons by studying the properties of electric discharge in cathode-ray tubes. According to Thomson's paper, the rays were deflected within the tube, which proved that there was something that was negatively charged within the vacuum tube.

In , Thomson published a description of his version of the atom, commonly known as the "plum pudding model. Scientists determine the atomic mass by calculating the mean of the mass numbers for its naturally-occurring isotopes. Often, the resulting number contains a decimal. For example, the atomic mass of chlorine Cl is Given an atomic number Z and mass number A , you can find the number of protons, neutrons, and electrons in a neutral atom.

Isotopes are various forms of an element that have the same number of protons, but a different number of neutrons. Isotopes are various forms of an element that have the same number of protons but a different number of neutrons.

Some elements, such as carbon, potassium, and uranium, have multiple naturally-occurring isotopes. Isotopes are defined first by their element and then by the sum of the protons and neutrons present.

While the mass of individual isotopes is different, their physical and chemical properties remain mostly unchanged. Isotopes do differ in their stability. Carbon 12 C is the most abundant of the carbon isotopes, accounting for Carbon 14 C is unstable and only occurs in trace amounts.

Neutrons, protons, and positrons can also be emitted and electrons can be captured to attain a more stable atomic configuration lower level of potential energy through a process called radioactive decay.

The new atoms created may be in a high energy state and emit gamma rays which lowers the energy but alone does not change the atom into another isotope. These atoms are called radioactive isotopes or radioisotopes. Carbon is normally present in the atmosphere in the form of gaseous compounds like carbon dioxide and methane. Carbon 14 C is a naturally-occurring radioisotope that is created from atmospheric 14 N nitrogen by the addition of a neutron and the loss of a proton, which is caused by cosmic rays.

This is a continuous process so more 14 C is always being created in the atmosphere. Once produced, the 14 C often combines with the oxygen in the atmosphere to form carbon dioxide. Carbon dioxide produced in this way diffuses in the atmosphere, is dissolved in the ocean, and is incorporated by plants via photosynthesis.

Animals eat the plants and, ultimately, the radiocarbon is distributed throughout the biosphere. In living organisms, the relative amount of 14 C in their body is approximately equal to the concentration of 14 C in the atmosphere. When an organism dies, it is no longer ingesting 14 C, so the ratio between 14 C and 12 C will decline as 14 C gradually decays back to 14 N. This slow process, which is called beta decay, releases energy through the emission of electrons from the nucleus or positrons.

After approximately 5, years, half of the starting concentration of 14 C will have been converted back to 14 N. This is referred to as its half-life, or the time it takes for half of the original concentration of an isotope to decay back to its more stable form.

Because the half-life of 14 C is long, it is used to date formerly-living objects such as old bones or wood. Comparing the ratio of the 14 C concentration found in an object to the amount of 14 C in the atmosphere, the amount of the isotope that has not yet decayed can be determined.

On the basis of this amount, the age of the material can be accurately calculated, as long as the material is believed to be less than 50, years old. This technique is called radiocarbon dating, or carbon dating for short.

Application of carbon dating : The age of carbon-containing remains less than 50, years old, such as this pygmy mammoth, can be determined using carbon dating. Other elements have isotopes with different half lives. For example, 40 K potassium has a half-life of 1.