Which of the following are molecular solids and which are covalent solids?
1. se8
2. hbr
3. si
4. co2
5. c
6. p4o6
7. sih4

Covalent solids: Se8, Si, C

Molecular solids: HBr, CO2, P4O6, SiH4

Explanation:

A covalent solid consists only of one type of atom infinitely linked by covalent bonds to form a three dimensional rigid solid while a molecular solid consists of discreet molecules held together by intermolecular forces.

it would be a gas formation

metals are good conductor of electricity. it has free electrons on their surface. according to electron pool theory, each atom present in a metal crystal losses all of its valence electron and as a result a pool of free is form. these pool of electrons are free to move and   conduct electricity easily   while making metal as good conductor.

the correct answer is a. the ability of electrons to flow throughout the metal.

if it's not useful, feel free to report for mistake in answer.