Not understanding definition

[Miike012]

Homework Statement

Molecular Substance... Is a substance that has molecules, all of which are the same...

im guessing it means... C sub4 is a molecular substance but if it was just Carbon itself ... it would not be a molecular substance because it is just an element and not a molecule... is this correct?

Homework Equations

The Attempt at a Solution

 

[HallsofIvy]

No, a molecule can consist of a single atom. And 4 Carbon atoms linked as a single group would certainly be a "molecule".

 

[Miike012]

I understand that if 4 carbons are linked together is a molecule However if it is just One carbon atom therefore because it is just a single atom and not a group of atoms chemically bonded that means it is not a molecule... is this correct?

 

[Borek]

Webster: (molecule is) the smallest physical unit of an element or compound, consisting of one or more like atoms in an element and two or more different atoms in a compound.

 

[Bohrok]

Wow, my world has been shattered a little... (not really) My understanding had always been like the first sentence on Wikipedia's article on http://en.wikipedia.org/wiki/Molecule" [Broken]: A molecule is defined as a group of at least two atoms in a definite arrangement held together by covalent chemical bonds.

So by Webster's definition, could Na(s) and He(g) also be considered molecules?

 

[Borek]

Read fine print in wikipedia.

I am not sure how to treat solid Na - it is a metal, so there is a metallic bond involved. He(g) is a molecule.