CROSSWORD NO. 1

3. Boron, Aluminum, Galium etc. are ____ conductors.
7. Molecules can be subdivided chemically into minute particles known as ______.
8. Lithium, Sodium, Potassium etc. have ____ valency.
9. The materials which have three electrons in their outer shell are called ___ Valent materials.
10. ________ has no charge at all.
11. An example of semiconductor material.
13. Materials which have 7 electrons in their outer shell are Good __________.
15. ____ has the main role to classify any material on the basis of its atomic structure.

1. An atom may be regarded as the _______ particle of an element that can exist.
2. _______ has a positive electrical charge.
4. This type of energy is most convenient form of energy and has many applications.
5. Name of material whose atomic number is 6.
6. Matter is made up of extremely small particles known as _______.
12. Central part of an atom is called as _______.
14. Classification of materials used in engineering can be done on the basis of their __structure.