The transition metals (with the exception of Zn, Cd and Hg) are very much hard and have low volatility. Why Zn ,Cd and Hg has low melting points. (a) These have all their electrons paired. (b) These have maximum number of unpaired electrons. (c) These have very strong metallic bonding. (d) These have more metal-metal bonding.

Zn ,Cd and Hg has low melting points because - These have all their electrons paired.

Explanation:

Hence , the correct option is A (These have all their electrons paired).

explanation:

crosscutting concepts have application across all domains of science. as such, they are a way of linking the different domains of science. they include patterns; cause and effect; scale, proportion, and quantity; systems and system models; energy and matter; structure and function; and stability and change.

definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.