what is atom and its components

Atoms is basic unit of matter which consist on three main component such as electron, proton and neutron. These component further comprised of quarks.

Proton: Atomic particles which are positively charged and present in the nucleus such as hydrogen has one proton in its nucleus and carbon has six proton. Numbers of proton in all atoms of an element always remain same.

Neutron: These are uncharged atomic particles and they are presents in nucleus such as hydrogen has no neutron and carbon has six neutron. Number of neutrons vary in atoms of same element which are called isotopes.

Electron: These are negatively charged atomic particles and present outside the nucleus such as hydrogen had on electron and carbon has six electron. The numbers of electron remain same in all neutral atom of same element.

The proton and neutron is collectively called nucleus.

The numbers of proton and neutron is always same in a neutral atom which the numbers of neutron can be different.

There are now 118 total element, which are listed in periodic table in form of row and column.

In periodic table elements are represented by symbols are shown below. This is sodium symbol represented by "Na" which atomic number at the top of symbol while mass number at the bottom of symbol. As sodium has 11 atomic number and 23 mass number.