Structure Of Atom

Project School

:

: Structure of Atom Govt.G.Sr.Sec.School Chamkaur Sahib Distt. Roopnagar( Punjab)

Class Teacher’s Trainer : Stundent’s Trainer : :

: 9th Ajay Gupta Mandeep Kumar Manpreet Kaur

Name of Students : Ramandeep Kaur Sonia Rani Jaspreet Kaur Jasvir Kaur

Jasvir Kaur Sarabjit Kaur

Structure of Atom An Atom consists of following parts. Nucleus :- It consists of protons and neutrons. It has +ve charge. It has very small size as compared to atom. The Mass of an atom is only due to its nucleus. Proton :Neutron :-

It has +ve charge. It has no charge.

Electrons :- These have –ve charge and they move freely around +ve charged nucleus.

Characteristics of an Atom Charge

Mass

Electron Proton

1.6 x 10-19 C

9.1 x 10-28 g

1.602 x 10-19 C

1.673 x 10-24 g

Neutron

No Charge

1.675 x 10-24 g

 Atomic Number : =

No. of Protons

 Atomic Mass :

No. of Protons + No. of Neutrons

=

Structure of Mg.Element Atomic No.

12

Atomic Mass : 24

Different Models of Structure of Atom Rutherford’s Model : Bohr’s Model :

Rutherford’s Model :  An Atom consists of +ve charged Nucleus.  -ve charged Electrons move around the Nucleus.  Its Model resemble a tiny solar system.

Bohr’s Model

 An Atom consists of +ve charged Nucleus.  -ve charged Electrons move around the Nucleus in quantized orbits.

Isotopes  Atoms of same element having different mass number are called isotopes of an element.  These isotopes exist due to different no of Neutrons in the nucleus of an atom of element.

List of Isotopes Element

Isotopes

Hydrogen Atomic. No.=1

Protium : Deutrium : Tritium : Helium-3 : Helium-4 : Carbon-12 : Carbon-13: Carbon-14:

Helium Atomic .No.= 2 Carbon Atomic No. = 6

Mass No. 1 Mass No. 2 Mass No. 3 Mass No. 3 Mass No. 4 Mass No. 6 Mass No. 7 Mass No. 8

Isotopes of Hydrogen Atom

Element Hydrogen

Symbol H

At.No. No.of Valency Electrons 1 1 +1

Helium

He

2

2

0

Lithium

Li

3

3

+1

Beryllium

Be

4

4

+2

Boron

B

5

5

+3

Carbon

C

6

6

+4

Element Nitrogen

Symbol At.No No.of . Electrons N 7 7

Valency -3

Oxygen

O

8

8

-2

Florin

F

9

9

-1

Neon

Ne

10

10

0

Sodium

Na

11

11

+1

Magnesium

Mg

12

12

+2

Alpha Decay •

A unstable radioactive element decay by releasing an Alpha particle. • An Alpha particle consists of two Protons and two Neutrons. • After releasing an Alpha particle ,the radioactive element give rise a new element.

Beta Decay • •

It occurs in two ways: In first way of Beta decay a neutron turns into proton by releasing a –ve charged particle and antineutrino. • In 2nd way of Beta decay a proton turns into neutron by releasing a +ve charged particle and a neutrino.