Why is Mercury a liquid at room temperature?

Answer 1

A solid melts when the available energy in heat exceeds the energy required to break up the solid, which is equal to the extra energy gained by letting the atoms stay always close to one another rather than passing only occasionally near like ships

in the night. The simplest model of metals treats the valence electrons as

a gas around charged cores composed of the atoms minus their valence

electrons. Zn, Cd and Hg all have the same number of valence electrons (2)

and hence the same charge on their cores, *but* the volume each valence

electron has to move around in increases from 8 to 11 to 12 in units of

10^-24 cm^3, that is the gas of valence electrons becomes less dense. When

it is less dense, the electrons interact (favorably) with the oppositely

charged cores less often, so the extra energy gained by having cores and

electrons all close together is less, hence the extra energy of the solid

is less, hence the melting point lower. Why should the valence electron

gas get less dense? Not an easy question to answer, the density is a

delicate competition between the desire of all the electrons to get close

to the cores and their mutual repulsion. Since the Hg core is bigger (it

has more non-valence electrons in it) the electrons are squeezed anyway in

Hg by the core hogging more space, so you might guess the preferred density

might end up a little lower, as it does. This is simply because Mercury has a very low melting point (-38.83°C/234.32K), meaning it is only a solid when it gets cold enough.

Answer 2

Mercury has completely filled d10 electronic configuration. hence the extent of metallic bond formation is less as the orbitals are completely filled. due to weak interatomic forces of attraction, Hg exists as a liquid at room temperature

Answer 3

A solid melts when the available energy in heat exceeds the energy required to break up the solid, which is equal to the extra energy gained by letting the atoms stay always close to one another rather than passing only occasionally near like ships

in the night. The simplest model of metals treats the valence electrons as

a gas around charged cores composed of the atoms minus their valence

electrons. Zn, Cd and Hg all have the same number of valence electrons (2)

and hence the same charge on their cores, *but* the volume each valence

electron has to move around in increases from 8 to 11 to 12 in units of

10^-24 cm^3, that is the gas of valence electrons becomes less dense. When

it is less dense, the electrons interact (favorably) with the oppositely

charged cores less often, so the extra energy gained by having cores and

electrons all close together is less, hence the extra energy of the solid

is less, hence the melting point lower. Why should the valence electron

gas get less dense? Not an easy question to answer, the density is a

delicate competition between the desire of all the electrons to get close

to the cores and their mutual repulsion. Since the Hg core is bigger (it

has more non-valence electrons in it) the electrons are squeezed anyway in

Hg by the core hogging more space, so you might guess the preferred density

might end up a little lower, as it does. This is simply because mercury has a very low melting point (-38.83°C/234.32K), meaning it is only a solid when it gets cold enough.

Answer 4

The first ionization potential value for mercury is very high (partially because of "lanthanide contraction" (mercury is not itself a lanthanoid, but the contraction applies to all elements following lanthanum), but mainly because the 6s electrons in mercury are relativistic, increasing their mass which reduces their average distance from the nucleus which in turn results in an unusually strong attraction to the positively charged nucleus). This makes the metallic bond in mercury weak compared to other metals as the electrons are not as readily delocalizable, and weaker bonding leads to a lower melting point.