List of top Chemistry Questions on Classification

In comparison to boron, berylium has :

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

Which among the following elements is a metalloid?

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

Element A and B have electronegativities 3 and 1.2 respectively? Nature of bond between them?

Tertiary alkyl halide is practically inert to substitution by $S_N2$ mechanism because of

The electronic configuration with the highest ionization enthalpy is :

Which of the following atoms should have the highest $1^{\text{st}]$ electron affinity?

The following statements concern elements in the periodic table. Which of the following is true ?

The atom of largest size among the following is

Which one of the following elements has the highest negative value for its electron gain enthalpy?

The ionic radii (in $?$) of $N^{3-},O^{2-} $ and $F^-$ respectively are

In the long form of the periodic table, the valence shell electronic configuration of $5s^2 5p^4$ corresponds to the element present in :

Among $P, S, Cl, F$, the elements with most negative and least negative electron gain enthalpy respectively, are

Among second period elements/the correct order for first ionisation enthalpy is

Which of the following arrangements represents the increasing order (smallest to largest) of ionic radii of the given species $O^{2-}, S^{2-}, N^{3-}, P^{3-} ?$

Similarity in chemical properties of the atoms of elements in a group of the Periodic table is most closely related to :

Which of the following series correctly represents relations between the elements from X to Y?
\(X\to Y\)

What are lanthanides and actinides?

First ionisation enthalpy of ${Al}$ is lower than that of ${Mg}$. This is because

In the $3^{rd}$ period, the first ionisation potential is of the order

In the periodic table, the period number corresponds to

The order of increasing sizes of atomic radii among the elements $O, S, Se$ and $As$ is :

The first ionisation potential of $Na$ is $5.1\, eV$. The value of electron gain enthalpy of $Na^+$ will be