Periodic Properties and Their Trends

What is electronegativity?

In which of the following arrangements, the order is/are not according to the property indicted: 

The first ionisation enthalpies $\left({∆}_{\mathrm{i}}{\mathrm{H}}_1\right)$, second ionisation enthalpies $\left({∆}_{\mathrm{i}}{\mathrm{H}}_2\right)$ and electron gain enthalpy $\left({∆}_{\mathrm{eg}}\mathrm{H}\right)$ of the elements $\mathrm{I}, \mathrm{II}, \mathrm{III}, \mathrm{IV}$ and $\mathrm{V}$ are as follows:

The most reactive metal and the least reactive non-metal of these elements are respectively

How much energy in joules must be needed to convert all the atoms of sodium ions present in $2.3 \mathrm{mg}$ of sodium vapours? Ionisation enthalpy of sodium is $495 \mathrm{kJ}/\mathrm{mol}$.

The amount of energy released when one million of atoms of iodine in vapour state are converted to ${\mathrm{I}}^{-}$ ions is $4.9\times {10}^{-13} \mathrm{J}$ according to the reaction: $\mathrm{I}\left(\mathrm{g}\right) + {\mathrm{e}}^{-} \to {\mathrm{I}}^{-}\left(\mathrm{g}\right)$

Express the electron gain enthalpy of iodine in terms of ${\mathrm{kJmol}}^{-1}$ and $\mathrm{eV}$ per atom.

Explain the various factors that affect electron affinity.

Calculate the electronegativity value of fluorine on Mulliken’s Scale, given that -

• Ionisation potential of $\mathrm{F}=17.4 \mathrm{eV}/\mathrm{atom}$
• Electron affinity of $\mathrm{F}=3.62 \mathrm{eV}/\mathrm{atom}$

How Ionisation energy of an atom is affected by nuclear charge ?

Explain the acid strength of oxoacids of chlorine?

How the acidic strength of hydrides down the group?

Arrange $\mathrm{B}\mathrm{e},\mathrm{}\mathrm{M}\mathrm{g},\mathrm{}\mathrm{C}\mathrm{a},\mathrm{}\mathrm{S}\mathrm{r}$ in the ascending order of ionisation enthalpy.

The correct order of $1^{\mathrm{st}}$ ionisation enthalpy among the following elements $\mathrm{Be}, \mathrm{B}, \mathrm{C}, \mathrm{N}, \mathrm{O}$ is

Amongst isoelectronic species, smaller the positive charge on the cation, smaller is the ionic radius.

Name the element with maximum electron affinity.

Which among the following species has the same number of electrons in its outermost as well as penultimate shell ?

The correct arrangement for the ions in the increasing order of their radii is

The correct order of decreasing ionic radii among the following isoelectronic species is

For ${\mathrm{Na}}^{+} , {\mathrm{Mg}}^{2+} , {\mathrm{F}}^{-} \mathrm{and} {\mathrm{O}}^{2-}$ the correct order of increasing ionic radii is

The sizes of following species increase in the order:

The formation of the oxide ion ${\mathrm{O}}^{2-}$(g) requires first an exothermic and then an endothermic step as shown below: $\mathrm{O}\left(\mathrm{g}\right)+{\mathrm{e}}^{-1}\to {\mathrm{O}}^{-}\left(\mathrm{g}\right);∆{\mathrm{H}}^0=-142 \mathrm{k}\mathrm{J} \mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$
${\mathrm{O}}^{-}\left(\mathrm{g}\right)+{\mathrm{e}}^{-1}\to {\mathrm{O}}^{2-}\left(\mathrm{g}\right);∆{\mathrm{H}}^0=+844 \mathrm{k}\mathrm{J} \mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$
This is because