Question

What determines if an element is a solid or liquid at room temperature? this isn't a test question BTW.

Answer 1

Actually its easy to remember all, at room temperature, Almost all the elements are in solid phase.
Exceptions:
Liquids at room temperature are Bromine and Mercury only.
Gases at room temperature are Noble Gases, Nitrogen, Oxygen, Fluorine and Chlorine. (You can remember it like diatomic molecules except for Mercury)

Answer 2

The intermolecular forces and the electron configuration of the element in it's ground state determines it's state.

Answer 3

Eh, it's complicated. Noble gases and nonmetals that form strong molecules (H2, N2, O2 and the halogens) can only hold together by weak intermolecular dispersion forces, so these will be gases at room temperature, unless the atoms are quite heavy, which explains why Br2 is liquid and I2 is solid. (Note also that radon boils at -71C, and for all we know the noble gas underneath it, if enough of it could ever be made, might be a liquid at room temperature.)

Nonmetals that form extended networks, like carbon and to some extent others in Group 4A, will need to break chemical bonds to melt or boil, so they'll be solids. Nonmetals that form quite large molecules, like S (S8) and P (P4) will also be solids, because of the large dispersion forces, but low-melting solids.

Metals form strong chemical bonds to each other in the solid state, so they are almost all solids. The eceptions tend to be heavy metals with few valence electrons, or few effective valence electrons, so the bonds they form with other atoms are weak. Examples are cesium and francium, Group 1A metals that melt at 30 C, gallium, which also melts at 30 C and acts like a Group 1A metal because it has only one effective valence electron, and mercury, which melts at -35 C because it acts almost like a noble gas, with zero effective valence electrons.

Answer 4

Awesome! thank you all very much and Im sorry I coulndt reply to your answers earlyer! I was at school at the time studying for a project, thanks!

Answer 5

@Carl_Pham Thank you very much for the extended response, I appreciate your effort verily.