Q12.80 P - Chemistry: Molecular Nature Of Matter And Change

Question

Both solid Kr and solid Cu consist of individual atoms. Why do their physical properties differ so much?

Step-by-Step Solution

Answer

The physical properties of solid Kr and solid Cu are different because Kr is a noble gas with complete octet configuration which renders weak London dispersion forces.

Step1: Intermolecular force of attraction in solid Kr

Krypton (Kr) is a noble gas with complete octet, thus there are no ionic forces involved in the solid Kr and only weak intermolecular London forces of attraction are present.

Step2: Difference in the physical properties

Solid Kr shows different physical properties than solid Cu, because in solid Kr only weak dispersion forces are present, whereas the solid Cu is not a noble metal and has two valance electrons. Thus, due to the difference in the intermolecular forces between the atoms, there is a difference in the physical properties.