# Atomic structure

## ATOMS

Atoms present in all particles of matter. They are small and size 100 Pico meters. Every solid, liquid, gas and plasma composed of neutral or ionized atoms. It arises from the Greek word atomos ‘indivisible’ meaning uncuttable. The atomic structure comprises of protons and neutrons surrounded by an electron.

BASIC MODEL OF ATOM

An atom consists of three elements, namely electrons, protons, and neutrons. Protons and neutrons together called as nucleons present in the nucleus. The nucleus is the center part of the atom, it consists of 99.94% mass of an atom.

## ELECTRONS:

The electrons negative charged particles. The volume of an atom occupied by a number of electrons. When a number of protons are equal to the number of electrons, the atom is electrically neutral. When the number of electrons is more or lesser than a number of protons, known as ions. The protons and electrons attracted by electromagnetic force while the protons and neutrons attracted by nuclear force.

The number of electrons defines the magnetic properties of an atom. Electrons belong to the first generation of the lepton particles because they have no known components or substructure. The electrons have a mass 1/1836 that of the proton. The charge of an electron is 1.602×10−19. An electron can act as a wave. This called wave-particle duality. Electrons are identical particles because they are similar by their intrinsic physical properties. In quantum mechanics, this means that a pair of interacting electrons must be able to swap positions without an observable change to the state of the system. The electrons forced by electromotive force. It measured in volts.

Current and Voltage:

Pressure and the quantity of electricity transmitted considered analogous to pressure and quantity of water flowing in pipes: the longer the distance, the higher is the pressure (called the “voltage” for electricity) necessary to pump the flow of water (called the “flow of electrical charge, which is also known as the “electric current”). That is why, for long distance transmission, high pressure (voltage for electricity) required, failing which, the current – and therefore the power – will not reach the intended destination. Instead, it’s lost (also called “dissipate”) along the way.

## PROTONS AND NEUTRONS:

The word Proton is from Greek meaning “First”. The number of protons in an atom defines the chemical element of an atom belongs. The number of neutrons defines isotope of the element. The combinations of an atom are generally called as molecules. The number of protons denoted by an alphabet Z and the number of neutrons denoted by an alphabet N. The sum of a number of protons and number of neutrons called as an atomic mass of an atom. The charge of a proton is the same as an electron but with a positive sign. Protons and Neutrons bound together by Nuclear force to form atomic nuclei.

BASIC CHARACTERISTICS OF ATOMS

• Atom is a basic chemical building block of matter.
• The charge of proton and electron are equal in magnitude, yet opposite in sign.
• The size of a proton is equal to the size of the electron, whereas the size of an electron is lesser than the size of protons and electrons.
• The mass of a proton is 1840 times greater than the mass of an electron.
• The atom consists of shells which sometimes resembles in spheres, dumbbell, and other shapes.
• Electrons can be found anywhere in the atoms not only in the orbit shells.
• The strong force that binds together protons, neutrons is 1038 times more powerful than gravity.

## ELECTRONIC CONFIGURATION

An electronic configuration table is a type of code that describes how many electrons are in each energy level of an atom and how the electrons arranged within each energy level. If you make a model of an atom a need to know how to place the electrons around the nucleus? If so, you will need to know how to read an element’s electronic configuration table.

EXAMPLE: Gold

Gold

Electronic configuration

 Electronic configuration 1s22s22p63s23p63d104s24p64d105s25p64f145d106s1

The first number is the energy level. We can tell right away that an atom of gold contains 6 energy levels. The lowercase letter in the subshell named s,p,d,f. The number of available subshells increases as the energy level increases. For example, the number in superscript is the number of electrons in a subshell. Each subshell can hold only a certain number of electrons. The s subshell can hold no more than 2 electrons, the p subshell can hold 10 and the f subshell holds as many as 14. The number of electrons in an energy level known by adding the superscript. The atom outermost energy level is 6s.

## FACTS OF AN ATOM

• There are over 100 different kinds of atoms.
• About 92 of them occur naturally while the remaining is made in labs.
• The first new atom made by man was technetium, which has 43 protons.
• New atoms made by adding more protons to the atomic nucleus. New atoms are unstable.
• The largest atom is cesium which is 9 times bigger than the smallest atom (helium).
• Other than protons, electrons, and neutrons, the atom has finer particles like leptons and quarks.
• A hydrogen atom considered as one of the most atom present in the world, milky way galaxies have hydrogen atoms.