About Atomic Structure
The atom is the building block that makes up our diverse universe. Once though to be the smallest unit of matter we now understand that the atom is made up of smaller parts called subatomic particles. The arrangement of these subatomic particles, called the atomic structure, is important for understanding the nature of matter.
Other People Are Reading
-
History
-
Our modern understanding of the structure of the atom has been developed over the past 200 years. The first useful atomic theory was developed in the 1800's by British scientist John Dalton who proposed the existence of the electron. In 1911 physicist Ernest Rutherford discovered the nucleus and his theories were further developed by scientists Max Planck and Niels Bohr.
Features
-
Atoms are made of three basic particles; negatively charged electrons, neutrally charged neutrons and positively charged protons. The neutrons and protons are located in the center of the atom, called the nucleus. In the current theory of atomic structure the electrons are described as existing in specific regions around the nucleus called an orbital or a valance shell. The electrons are able to release or absorb energy based on their movement between the valance cells. Subatomic particles are now known to also be made of even smaller components called quarks.
-
Size
-
Most of an atom, up to 99 percent, is empty space. An atom's mass is located mostly in one dense region, the nucleus. Because atoms are so small and difficult to measure they are usually classified according to mass, not size. When the size of an atom does need to be determined it is done by measuring between the nuclei of two atoms of the same element and then dividing by two.
Types
-
Each unique atom is called an element. Elements differ from one another in the number of protons they contain. This number of protons is called the atomic number and atoms of an element all have the same atomic number. The 94 natural and 23 lab-created elements are arranged in the periodic table by their atomic number and mass.
Significance
-
An understanding of the structure of the atom is vital for determining the nature of all matter. All modern day science is built around the fundamental knowledge of how the atom is constructed. Physics, chemistry, biology and all of their branches rely heavily on atomic structure to predict how matter will react and interact in our world.
-
Resources
- Photo Credit stock_xchng - Atom (stock photo by jayofboy) [id 1054338]
