Question

information regarding periodical development of fundamental particles and structure of atoms

Answer 1

the atom is element which has no. of protons and neutron forms in nucleus of atom, which fundamentally contained but their activity can be seen the no. of electrons are present its outermost shell.

The 2nd half of 9th century the data from different countries e.g. France, England , and Germany was collected from laboratories , in this way Italy were assembled in the pamphlet .In this pamphlet the data which demonstrates that atoms keep some weight this was established by Cannizzaro.

The after Cannizzaro then Mendeleyev works more on atoms and discovers most of information about the atoms He who first determine the atoms arrangement as increasing orders .so here two things of atomic data was collected first was weight and second was arrangement of atoms.

elements increasing order atomic weigh is similar properties which repeating at regular intervals.

he  Mendeleyev periodic table used to describes repetition of chemical and physical properties of atoms to make a Table which was  like to the Periodic Table using in these days.

John Thomson in 20th century was discovered the neutrons were exist in the nucleus.

So existence of neutrons in nucleus it determines the weight of atoms is due to neutrons present in nucleus.

In this way they concludes that the atomic size and weight are different so due to difference of their weight its protons and neutrons no. also different.

Examples : H1 , He2. Li3 etc.

Answer 2

Periodical development of fundamental particles :

• About 2600yrs  ago, an Indian sage called Kanada actual called by name Kasyapa proposed that all forms of matter are composed of very small particles called as Anu and each anu may be made up of still smaller particle called Parmanu.

• Later Democritus called these atoms [ greek Word "Atomio " meaning indivisible "

• John Dalton atomic theory described elements in terms of atoms which he believed to be small , indivisible particles.

• Later John Dalton's Postulate Atom is indivisible is disproved because through various experiments conducted by scientist three fundamental particles were discovered

1. Electron --- By J.J Thomson in 1897

1. Proton --- By Gold Stein in 1920

1. Neutron --- By James Chadwick in 1932

Structure of Atom:

Thomson Atomic model:

•         After the discovery of electrons J.J Thomson proposed his Plum Pudding model which shows electrons embedded through out the mass of positively charged material.

• Rutherford alpha scattering experiment led to discovery of atomic nucleus.

• Neil Bohr modified Rutherford Model of the atom by stating that electrons move in specific energy levels around Nucleus of atom.

• Later Bohr Sommerfeld model though successful in accounting for the spectral line of H2 spectra but did not provide satisfactory picture of the structure of atom in general.

At last A quantum mechanical model of atom was developed by Erwin Schrodinger. According to this model, electrons are present in a particular region or space around the nucleus called as Orbital where probability of finding electrons are more.