Explain why aluminium has a lower first ionisation energy than magnesium. 

Important Questions on Classification of Elements and Periodicity in Properties

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The effective nuclear charge of an element with three valence electrons is $2.60$ . What is the atomic number of the element?

MEDIUM

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

Which of the following represents the correct order of increasing first ionization enthalpy for $\mathrm{Ca}, \mathrm{Ba}, \mathrm{S}, \mathrm{Se} \text{and} \mathrm{Ar}$?

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The first ionization enthalpies for three elements are $1314, 1680$ and $2080\mathrm{ }\mathrm{kJ}\mathrm{ }{\mathrm{mol}}^{-1}$ , respectively. The correct sequence of the element is:

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

Among the element Li, N, C and Be, one with the largest atomic radius is

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

When the first electron gain enthalpy $\left({\mathrm{\Delta H}}_{\mathrm{eg}}\right)$ of oxygen is $-141\mathrm{ }\mathrm{kJ}/\mathrm{mol}$ , its second electron gain enthalpy is:

MEDIUM

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The electronegativities of $N, C, Si$ and $P$ are in the order -

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The species $\mathrm{A}\mathrm{r},\mathrm{ }{\mathrm{K}}^{+}$ and $\mathrm{C}{\mathrm{a}}^{2+}\mathrm{ }$ contain the same number of electrons. In which order do their radii increase?

MEDIUM

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

Which one of the following has largest ionic radius ?

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The correct order of atomic radii is:

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The formation of the oxide ion, ${\mathrm{O}}^{2-}\left(\mathrm{g}\right)$ , from oxygen atom requires first an exothermic and then an endothermic step as shown in below:

$\mathrm{O}\left(\mathrm{g}\right)+{\mathrm{e}}^{-}⟶{\mathrm{O}}^{-}\left(\mathrm{g}\right)\mathrm{ }\mathrm{ }\mathrm{ };\mathrm{ }\mathrm{ }{\mathrm{\Delta }}_{\mathrm{f}}{\mathrm{H}}^{\ominus }=-141\mathrm{ }\mathrm{k}\mathrm{J}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$

${\mathrm{O}}^{-}\left(\mathrm{g}\right)+{\mathrm{e}}^{-}⟶{\mathrm{O}}^{2-}\mathrm{ }\left(\mathrm{g}\right)\mathrm{ };\mathrm{ }\mathrm{ }{\mathrm{\Delta }}_{\mathrm{f}}{\mathrm{H}}^{\ominus }=+780\mathrm{ }\mathrm{k}\mathrm{J}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}$

Thus process of formation of ${\mathrm{O}}^{2-}$ in gas phase is unfavourable though ${\mathrm{O}}^{2-}$ is isoelectronic with neon. It is due to the fact that,

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The electronic configuration with the highest ionization enthalpy is:

MEDIUM

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

In which of the following options the order of arrangement does not agree with the variation of property indicated against it?

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The electronic configuration of an element with the largest difference between the $1^{st}$ and $2^{nd}$ ionization energies is

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

Which element has the highest first ionization potential?

MEDIUM

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

In the following sets of reactants which two sets best exhibit the amphoteric character of Al₂O₃ . xH₂O ?

$\begin{array}{cc}\text{Set I}& {\text{Al}}_2{\text{O}}_3·{\text{xH}}_2{\text{O}}_{\left(\text{s}\right)}+{\text{OH}}_{\left(\text{aq}\right)}^{-}\\ \text{Set II}& {\text{Al}}_2{\text{O}}_3\text{x}·{\text{H}}_2{\text{O}}_{\left(\text{s}\right)}+{\text{H}}_2{\text{O}}_{\left(\mathit{\text{l}}\right)}\\ \text{Set III}& {\text{Al}}_2{\text{O}}_3\text{x}·{\text{H}}_2{\text{O}}_{\left(\text{s}\right)}+{\text{H}}_{\left(\text{aq}\right)}^{+}\\ \text{Set IV}& {\text{Al}}_2{\text{O}}_3·{\text{xH}}_2{\text{O}}_{\left(\text{s}\right)}+{\text{NH}}_{3\left(\text{aq}\right)}\end{array}$

HARD

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The option(s) with only amphoteric oxides is(are):

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

Which of the following atoms has the highest first ionization energy?

EASY

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The first ionisation potential of Na is 5.1 eV. The value of electron gain enthalpy of Na ⁺ will be :

HARD

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

Among the following, the correct order of acidity is:

MEDIUM

Chemistry>Inorganic Chemistry>Classification of Elements and Periodicity in Properties>Periodic Trends in the Properties of Elements

The ionic radii $\left(\text{in}\mathrm{ Å}\right)$ of ${\mathrm{N}}^{3-},\mathrm{ }{\mathrm{O}}^{2-}\mathrm{ }$ and $\mathrm{ }{\mathrm{F}}^{-}\mathrm{ }$ are respectively: