The electrostatic force of attraction between the positively charged atomic nuclei of metal atoms and the delocalized electrons in the metal is known as:

Electrons used in the formation of chemical bonds are called?s

The H-C-H bond angle in methane is: 

First statement: Ionic compounds conduct when molten or in aqueous solution (i.e. dissolved in water) but not when solid.
Second Statement: When molten or in aqueous solution, their ions are mobile i.e. free to move about and transfer charge from one point to another.
In the solid state, the ions are tightly bound together by strong ionic bonds and cannot move.