When copper reacts with hot and conc. H₂SO₄ gives

• H₂

• N₂

• O₂

• SO₂

BaO₂ and ozone reacts to produce

• Ba

• Ba₂O₃

• BaO

• Ba(OH)₃

253.

The set representing the correct order for first ionisation potential is

• K > Na > Li

• Be > Mg > Ca

• B > C > N

• Ge > Si > C

A nuclide of an alkaline earth metal undergoes radioactive decay by emission of three $\mathrm{\alpha }$-particles in succession. The group of the periodic table to which the resulting daughter element would belong to

• Group 14

• Group 16

• Group 4

• Group 6

The first ionisation enthalpy of boron is less than beryllium because:

• Boron has high nuclear charge

• The size of boron atom is more than beryllium atom

• p-subshell of boron has only one electron

• The size cit boron atom is less than beryllium atom

What will be the order of I^st ionisation energy?

• Li > Na > K

• K > Li > Na

• Na > Li > K

• Li > K > Na

Which of the following statement(s) is/are correct regarding shielding effect?

• The magnitude of screening effect do not depends upon the number of inner electrons

• The magnitude of effective nuclear charge decreases in a period.

• Greater the shielding effect, lower will be the atomic radii

• For a given 'orbit' the shielding effect of electron belonging to different subshell decrease in the order s > p > d >f

The incorrect configuration is

• K = [Ar] 4s¹

• Cr= [Ar] 3d⁵ ,4s¹

• Cr= [Ar] 3d⁴ , 4s¹

• Cu= [Ar]3d¹⁰ ,4s¹

Which of the following ions has the highest value of ionic radius:

• O^2-

• F^-

• Li⁺

• B³⁺

Which of the following ions, has smallest size?

• Ca²⁺

• Cl^-

• S^2-

• K⁺