Which metal can displace iron from iron(II) sulfate solution? MCQ with Answer and Explanation

Explanation:
The modern periodic law, established by Henry Moseley, states that the properties of elements are periodic functions of their atomic numbers. Mendeleev’s original table was based on atomic mass, but the modern version uses atomic number which resolves anomalies like Ar (Z=18, mass 40) and K (Z=19, mass 39).

Explanation:
CaSO₄·½H₂O readily absorbs moisture to set to CaSO₄·2H₂O (gypsum), becoming hard and useless for molding. So it must be kept dry. Reaction: CaSO₄·½H₂O + 1½H₂O → CaSO₄·2H₂O.

Explanation:
Electron affinity is the energy change when an electron is added to a neutral gaseous atom. It represents the tendency to gain electrons. Ionization energy is the energy to remove an electron. Electropositivity and metallic character relate to the tendency to lose electrons and form positive ions.