The document describes the structure of the atom, focusing on subatomic particles: electrons, protons, and neutrons. It details Niels Bohr's 1913 atomic model, which introduces the concept of fixed orbits for electrons around the nucleus, with each orbit having a specific energy level. The energy dynamics between orbits include emission and absorption of energy as electrons shift between levels.

1. STRUCTURE OF ATOM
Archa S R
BEd Physical Science

2. NIELS BOHR ATOM MODEL

3. Let’s recall the subatomic particles….
1. ELECTRON
 Negatively charged subatomic particle.
 Present in the orbits.
 Revolves around the nucleus
 Have mass.
 Number of electrons in an atom equal to the number of protons in that atom.

4. 2. Proton
•Positively charged subatomic particle
•Present inside the Nucleus.
•Gives positive charge to the nucleus.
•Have mass.
•Number of protons in an atom equal to the number of electons in that
atom.

5. 3. Neutron
•Chargeless particles inside the
nucleus.
•Have mass.

7. NEILS BOHR
•To overcome the limitations
of Rutherford atom model,
the Danish scientist Niels
Bohr proposed his atom
model in 1913.

8. Main Concepts Of Bohr Atom Model
1. Electrons revolve around the nucleus of an atom in fixed orbits.

9. 2. Orbits can be represented by giving numbers or alphabets like
1,2,3,4 or K,L,M,N respectively.

10. 3. Electrons in each orbit have a definite energy. So orbits
are also known as energy levels.

11. 4. As long as the electrons revolve in a particular orbit their energy
does not change. So, the orbits are known as stationary energy
levels.

12. 5. Energy of the orbit increases as the distance from the
nucleus increases.

13. 6. Energy is emitted when the electrons shift from orbits
of higher energy to orbits of lower energy.

14. 7. Energy is absorbed when electrons shift from
orbits of lower energy to orbits of higher energy.

16. BOHR ATOM MODER- HYDROGEN AND CHLORINE

17. Thank you