Chemistry Fill in the blanks Set 25

Chemistry Fill in the blanks Set 25

1. In NaCl ionic crystal each Na+ ion is surrounded by 6 Cl- ions
and each Cl- ion is surrounded by 6 Na+ ions.
 
2.The coordination number of Cs+ in CsCl crystal is 8
 
3. Amorphous solids do not possess sharp melting points and can be 
considered as super cooled liquids.
 
4. A body centred unit cell has an atom at the each vertex and at centre of the unit cell.
 
5. The three types of cubic unit cells are simple cubic, fcc and bcc
 
6. A crystal may have a number of planes or axes of symmetry but it possesses only one centre of symmetry.
 
7. Amorphous solids that exhibit same physical properties in all the directions 
are called isotropic.
 
8. Crystalline solids that exhibit different physical properties in all directions are called anisotropic.
 
9. The number of atoms in a single unit cell of cubic close packedsphere is 4
 
10. In a bcc, an atom of the body centre is shared by 1 unit cell.