d and f BLOCK ELEMENTS

Why is Mn3+ considered an oxidizing agent despite having a d4 electron configuration?

• Because it readily loses electrons to achieve a d3 configuration.
• Because the d4 configuration is inherently unstable.
• Because its configuration changes to the less stable d6 configuration upon gaining an electron.
• Because its configuration changes to the highly stable d5 configuration with a half-filled d subshell upon gaining an electron.

Why is Cr2+ considered a reducing agent despite having a d4 electron configuration?

• Because it readily gains electrons to achieve a d6 configuration.
• Because the d4 configuration is inherently unstable.
• Because its configuration changes to the more stable d5 configuration upon losing an electron.
• Because its configuration changes to the more stable d3 configuration with a half-filled t2g level upon losing an electron.

Why is the energy required to transform Cu(s) to Cu2+(aq) considered high?

• Due to copper's low atomization enthalpy.
• Due to copper's low hydration enthalpy.
• Due to copper's low ionization enthalpies.
• Due to copper's high atomization enthalpy and relatively high ionization enthalpies.

Which type of acids can react with copper metal?

• Only dilute acids.
• Only non-oxidizing acids.
• Only oxidizing acids.
• Any type of acid.

What accounts for copper's inability to liberate hydrogen gas from acids?

• Its negative standard electrode potential (E°).
• Its low ionization enthalpy.
• Its high hydration enthalpy.
• Its positive standard electrode potential (E°).