The atomic radii of inert gases are larger than those of preceding elements due to ............... (force of repulsion / high I.E.) in completely filled shells.

The atomic radii of group 13 elements are larger than those of group 2 elements. True/False.

Atomic radii of the transition elements are smaller than those of the s-block elements because:

Assertion : The order of atomic radii of Cu, Ag and Au is Cu lt Ag ~~ Au . Reason : The atomic radii of 4d series elements are larger than those of 3d series elements but generally the radii of 4d and 5d series elements are almost identical.

First IE of 5d seties element are higher than those of 3d and 4d series elements. This is due to:

Assertion : In transition elements radii of 5d series are virtually the same as those of the corresponding members of 4d series. Reason : The filling of 4f orbitals before 5d orbitals results in regular decrease in atomic radii.

How would you account for the following? (i)The atomic radii of the metals of the third (5d) series of transition elements are virtually the same as those of the corresponding members of the second (4d) series. (ii)The E^(@) value for the Mn^(3+)//Mn^(2+) couple is much more positive than that for Cr^(3+)//Cr^(2+) couple or Fe^(3+)//Fe^(2+) couple. (iii)The highest oxidation state of a metal is exhibited in its oxide or fluoride.

(a) Why alkaline earth metals are harder, have higer melting ponts and higher densities than the alkali metals? (b). Why the atoms of alkaline earth metals are smaller than the corresponding alkali metals? (c ). Why alkaline earth metals have high electrical and thermal conductivities? (d). What is black ash? (e). Why the variation in physical properties of alkaline earth elements is not as regular as in the case of alkali metals?

Statement-1 : Argon is used in the laboratory for handling substances that are air-sensitive. Statement-2 : Argon is inert towards chemical reactivity due to the completely filled valence shell electronic configuration, high ionization enthalpy and more positive electron gain enthalpy.

Figure, shown above, shows three situations involving a charged particle and a uniformly charged spherical shell. The charges and radii of the shells are indicated in the figure. If F_(1),F_(2) and F_(3) are the magnitudes of the force on the particle due to the shell in situations (I),(II) and (III) then

All the noble gases are colourless and tasteless monoatomic gases. In general, noble gases are least reactive and their inertness to chemical reactivity is attributed to the following reasons. Reactive and their inertness to chemical reactivity is attributed to the following reasons. (i)Except helium, all have completely filled ns^(2)np^(6) electronic configuration in their valence shells. (ii)All have high ionisation enthalpy and more positive electron gain enthalpy. However, a number of xenon compounds mainly with most electronegative elements like fluorine and oxygen have been synthesized under different conditions and fluorides of xenon have been used as an oxidising agent and a fluorinating agent in many of the chemical reactions The correct order of the abundance of various noble gases in air is :