8. Structure of Atom

1. The smallest unit of substances is called ________.

2. The central part of an atom is called _________.

3. Nucleus is made up of sub atomic particles like _________ and ________.

4. Visible light is an ____________ wave.

5. The speed of light (c) is _________ m/ s.

6. The electromagnetic energy is characterized by ________ and ______________.

7. A group of wave length or frequencies is called a _________.

8. The familiar example of the visible spectrum in nature is the formation of a ___________.

9. The range of wavelengths covering red colour to violet colour is called the ________________.

10. The entire range of wavelengths is known as the ___________.

11. In the equation E = hu, where ‘h’ is ___________ and ‘u’ is the frequency of light.

12. The value of h is __________ Js (Or) ____________ erg.Sec

13. Scientists found that each element emits its own characteristic colour. These colours correspond to certain discrete wavelengths of light and are called _________.

14. The states corresponding to these energies are called _____________ and the possible values of the energy is called energy levels.

15. The energy emitted by the electron is seen in the form of _______________ and when the wavelength is in the visible region it is visible as an emission line.

16. Bohr’s model explains all the line spectra observed in the case of _________ atom.

17. ___________ is a successful model as far as line spectra of hydrogen atom is concerned.

18. The line spectrum of hydrogen atom when observed through a high resolution ____________ appears as groups of finer lines.

19. Bohr’s model failed to account for splitting of ____________.

20. The nucleus of the atom is one of the principal foci of these ___________ orbits.

21. Somerfield was guided by the fact that, in general, periodic motion under the influence of a central force will lead to __________ orbits with the force situated at one of the foci.

22. _________ model failed to account for the atomic spectra of atoms of more than one
electron.

23. Max Karl Ernst Ludwig Planck was a German theoretical physicist who originated ______________ , which won him the Nobel Prize in Physics in 1918.

24. Planck made many contributions to theoretical physics, but his fame rests primarily on his role as originator of the ____________.

25. Electron revolves around the nucleus in defined paths called orbits or _________.

26. This short wavelength light interacts with the electron and disturbs the motion of the ___________.

27. Quantum mechanical model of atom was developed by ___________.

28. The region of space around the nucleus where the probability of finding the electron is maximum is called an _____________.

29. Each electron in an atom is described by a set of three numbers n, l, and ml.These numbers are called ______________.

30. Quantum numbersindicate the probability of finding the __________ in the space around the nucleus.