Q20 P - Chemistry: Molecular Nature Of Matter And Change

Question

In which compound does Cr exhibit greater metallic behaviour, CrF₂ or CrF₆? Explain.

Step-by-Step Solution

Answer

Cr exhibits greater metallic behaviour in CrF₂

Step 1: Metallic behaviour of metal

The level of reactivity of a metal is defined by its metallic character. Metals have low ionization energies, which indicates that they lose electrons in chemical processes. Metal atoms have a low attraction for electrons within a compound, as seen by their low electronegativities.

Step 2: Greater Metallic behaviour of compound

The transition metals with lower electronegativity have more metallic properties than ones with higher electronegativity (which have characteristics closer to nonmetals). It is known that fluorine has oxidation state of -l, so in CrF₂ chromium has oxidation state of +2 and EN value around 1.7, so its behaviour is more metallic than the chromium in CrF₆ (which has oxidation state of +6 and ENvalue around 2.3, thus it has more nonmetal behaviour).