The atomic number of the element unnilennium is :

Three elements X, Y and Z are in the 3^rd period of the periodic table. The oxides of X, Y and Z, respectively, are basic, amphoteric and acidic. The correct order of the atomic numbers of X, Y and Z is :

In general the property (magnitudes only) that show an opposite trend in comparison to other properties across a period is

The first and second ionisation enthalpies of a metal are 496 and 4560 kJ mol^–1, respectively. How many moles of HCl and H₂SO₄, respectively, will be needed to react completely with 1 mole of the metal hydroxide ?