Which of the following statement(s) is/are incorrect for pair of elements Zr-Hf?
Both possess same number of valence electrons
Both have identical sizes
Both have almost identical radii
Both of these belong to same period of periodic table
Which element among the following does not form diatomic molecules?
Argon
Oxygen
Nitrogen
Bromine
Choose the wrong statement from the following
The 'silver' UK coins are made of Ag/ Ni alloy
TiO2 is used in the pigment industry
MnO2 is used in the dry battery cells
V2O5 catalyses the oxidation of SO2 in the manufacture of sulphuric acid
The correct discending order of oxidising power of the following is
B.
Oxidising power depends upon the stability of reduction product obtained. Since, lower oxides of Mn are more stable than that of Cr and V, so the order of oxidising power is-
The number of electrons that are involved in the reduction of permanganate to manganese (II) salt, manganate and manganese dioxide respectively are
5, 1, 3
5, 3, 1
2, 7, 1
5, 2, 3
The ionisation enthalpy of He+ ion is 19.60 10-18 J atom-1. The ionisation enthalpy of Li2+ ion will be
84.2 × 10-18 J atom-1
44.10 × 10-18 J atom-1
63.20 × 10-18 J atom-1
21.20 × 10-18 J atom-1
Among the elements B, Mg, Al and K the correct order of increasing metallic character is
B < Al < Mg < K
B < Mg < Al < K
Mg < B < Al < K
Mg < Al < B < K