25. A solid substance is soft, has a low melting
point and is a poor conductor of electricity it is
D) An ionic solid
3) A metallic solid 4) A molecular solid
Answers
Answer:
A) Molecular Solid
Explanation:
Covalent solids are soft, have a low melting point (due to relatively weak bonds), and are a poor conductor of electricity (due to absence of free ions).
Answer:
4) A molecular solid
Explanation:
Covalent compounds have low forces of attraction between their molecules (i.e. one H2O molecule isn't as attracted to another H2O molecule than the oppositely charges ions are in an ionic compound). Little energy is needed to break their bonds, therefore they have low meting points.
Consequently, covalent compounds tend to be softer - the small attractive forces make the malleable. Ionic compounds are hard solids because the ions are very attracted to the other ions (due to electrostatic forces) and are stuck in a crystal lattice.
In any state (solid, gas, liquid or aqueous), covalent compounds are bad conductors. Their electrons are locked in places, and cannot carry a current. This is very unlike ionic compounds. When in aqueous or molten form, ionic compounds split up (for why - leave a comment or google it!) ions, which are able to carry a current. (However when in solid form, ionic compounds are BAD conductors- their ions cannot move- they're stuck in a crystal lattice)