An element (X) belongs to fourth period and fifteenth group of the periodic table. Which one of the following is true regarding the outer electronic configuration of (X)? It has

• partially filled d orbitals and completely filled s orbital

• completely filled s orbital and completely filled p orbitals

• completely filled s orbital and half-filled p orbitals

• half-filled d orbitals and completely filled s orbital.

Which of the following is a favourable factor for cation formation ?

• Low ionisation potential

• High electron affinity

• High electronegativity

• Small atomic size

Assertion : Generally alkali and alkaline earth metals form superoxides.

Reason: There is a single bond between O and O in superoxides.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false

• If both assertion and reason are false

Assertion : For hydrogen like species, energy of an electron in a particular orbit increases with increase in value of Z.

Reason : Electronegativity decreases across a period.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false

In a group of Periodic Table what is the basis of :

• ionic potential

• electron affinity

• electron negativity

• number of covalent electron

The correct electronic configuration of element with atomic number 29 :

• 1s² , 2s² 2p⁶ , 3s² 3p⁶ 3d¹⁰ , 4s¹

• 1s² , 2s² 2p⁶ , 3s² 3p⁶ 3d¹¹

• 1s² , 2s² 2p⁶ , 3s² 3p¹⁷

• None of the above

The correct size ofiodine atom and iodine ion is :

• I^- > I⁺ > I

• I > I⁺ > I^-

• I > I^- > I⁺

• I⁺ > I > I^-

The pair of amphoteric hydroxides is

• Be(OH)₂, Al(OH)₃

• Al(OH)₃, LiOH

• B(OH)₃, Be(OH)₂

• Be(OH)₂, Mg(OH)₂

279.

Assertion: The correct order of oxidising power is :

${\text{VO}}_2^{+}$ <  ${\text{Cr}}_2{O}_7^{2- }< MnO{ }_4^{-}$         

Reason: The oxidation state of Mn is +7

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

Which of the following element has lowest melting point?

• Cr

• Fe

• Ni

• Cu