definition of atom?

Answer 1

Atom is part of every good thing in world except "ATOM BOMB"

Answer 2

In chemistry and physics, an atom (Greek ἄτομος or átomos meaning "indivisible") is the smallest particle of a chemical element that retains its chemical properties. (átomos is usually translated as "indivisible." Until the advent of quantum mechanics, dividing a material object was invariably equated with cutting it.) Whereas the word atom originally denoted a particle that cannot be cut into smaller particles, the atoms of modern parlance are composed of subatomic particles:

electrons, which have a negative charge, a size which is so small as to be currently unmeasurable, and which are the least heavy (i.e., massive) of the three;
protons, which have a positive charge, and are about 1836 times more massive than electrons; and
neutrons, which have no charge, and are about 1838 times more massive than electrons.
Protons and neutrons make up a dense, massive atomic nucleus, and are collectively called nucleons. The electrons form the much larger electron cloud surrounding the nucleus.

Atoms can differ in the number of each of the subatomic particles they contain. Atoms of the same element have the same number of protons (called the atomic number). Within a single element, the number of neutrons may vary, determining the isotope of that element. The number of electrons associated with an atom is most easily changed, due to the lower energy of binding of electrons. The number of protons (and neutrons) in the atomic nucleus may also change, via nuclear fusion, nuclear fission or radioactive decay, in which case the atom is no longer the same element it was.

Atoms are electrically neutral if they have an equal number of protons and electrons. Atoms which have either a deficit or a surplus of electrons are called ions. Electrons that are furthest from the nucleus may be transferred to other nearby atoms or shared between atoms. By this mechanism atoms are able to bond into molecules and other types of chemical compounds like ionic and covalent network crystals.

Atoms are the fundamental building blocks of chemistry, and are conserved in chemical reactions

Answer 3

Well !!
Atoms are the unit or building blocks of an Element which can't be seen in open eyes.
They have 3 particles in them.The Core section contains Nucleus and the Shell section.

The core section contains Neutron(s) which is/are Neutral in charge and Proton(s) which is/are Positive in Charge.
The shell section contains Electron(s) which is/are Negative in Charge.

The Mass of Neutron and Proton are Same which is very much greater than Electrons.
So it's clear that we Electrons can be easily removed from an Atom with external Energy.
We can add or remove Electrons from and Atom.

The no. of Protons and Electrons are same in an Atom which makes them Neutral in Charge.
If there is an imbalance of the no of Neutrons and Electrons then the Atom is not Neutral in Charge.
Then we call them Ions.

Excess Electrons in Atom means the Atom is more Negatively Charged and then it's An-Ions.
Less Electrons makes an Atom more Positively Charges or Cat-Ions.

Learn How to Identify an Atom From Periodic Table :

1. Atomic No : The no. of Protons in an Atom which is same as no. of Electrons in a Neutral Atom.
2. Atomic Weight : Long Numbers with Decimal points.
3. Atomic Mass : Atomic Weight without Decimal points.
4. Neutrons : Atomic Mass - Atomic No.

Answer 4

The atom is the fundamental building block of all stuff, or what scientists like to call "matter". An individual atom is very small. In fact, the smallest type of atom, hydrogen, has a diameter of 10-8 cm. This means that if the hydrogen atom was the size of a soccer ball, then a soccer ball would be 6450 kilometers (4008 miles) high. Every single object is composed of atoms. Your body is made up of many, many individual atoms. There are also many different types of atoms. In fact, there are over a 100. These different types are called elements. Examples of some elements are hydrogen, oxygen, iron, copper, and helium. Under normal conditions many atoms can stick together to form larger, different stuff. Scientists call material that results from the joining of different types of atoms "compounds". An example of a compound is water, which is a group of two hydrogen atoms and one oxygen atom. Notice that we said that these types of compounds can only form under what we called "normal conditions". In the type of environment in which nuclear fusion occurs, the joining of atoms, also known as bonding, can't happen. We will explain why later.

Answer 5

The atom is the fundamental building block of matter.
Atoms are composed of sub-atomic particles called protons, electrons and neutrons. Protons carry a positive electrical charge, electrons carry a negative electrical charge and neutrons carry no electrical charge at all. The protons and neutrons cluster together in the central part of the atom, called the nucleus, and the electrons 'orbit' the nucleus in shells/orbitals. A particular atom will have the same number of protons and electrons and most atoms have at least as many neutrons as protons.

Answer 6

An atom is the smallest particle of an element which may or may capable of independent existence.Atoms of different elements differ from each other. An atom is composed of electrons protons and neutrons. atoms are the building blocks of matter.

Answer 7

in chemistry and physics, an atom (Greek ἄτομος or átomos meaning "indivisible") is the smallest particle of a chemical element that retains its chemical properties. (átomos is usually translated as "indivisible." Until the advent of quantum mechanics, dividing a material object was invariably equated with cutting it.) Whereas the word atom originally denoted a particle that cannot be cut into smaller particles, the atoms of modern parlance are composed of subatomic particles:electrons,protons,neutrons.

Answer 8

A simple definition of atom is that it is the smallest particle of an element and cannot be further divided.
Although it can be divided into protons,neutrons and electrons.

Answer 9

Atom is the smallest unit of a substance which can exist independently. It contains a nucleus in the centre which is made up of protons(+vely charged) and neutrons(no charge) and the electrons(-vely charged) revolve around the nucleus in elliptical orbit. There is a huge gap between the nucleus and the first shell of electrons.

Answer 10

this definition u could use to explain for a class.an atom is the smallest elemet on earth...it consits of neutrons,electrons and protons.. the charge of protons is = to 1+ and the charge of electrons is = to 1-. the neurtons has no charge. the mass of the atom is consits in its nucleus where the protons are found

Answer 11

A unit of matter, the smallest unit of an element, having all the characteristics of that element and consisting of a dense, central, positively charged nucleus surrounded by a system of electrons. The entire structure has an approximate diameter of 10-8 centimeter and characteristically remains undivided in chemical reactions except for limited removal, transfer, or exchange of certain electrons.