Observe the following data ($\Delta_i H_1$, $\Delta_i H_2$ and $\Delta_{eg}H$ represent the first, second ionisation enthalpies and electron gain enthalpy respectively).

Using the data identify the most reactive metal.

Question

Among the following the isoelectronic species are
I. $Mg^{2+}, Al^{3+}, F^-$
II. $O^{2-}, F^-, N^{3-}$
III. $K^+, Ca^{2+}, Sc^{3+}$
IV. $Mn^{2+}, Fe^{3+}, V^{3+}$

Answer 1

To determine the most reactive metal using the provided ionization and electron gain enthalpy data, we need to understand how these values correlate with metallic reactivity:

First Ionisation Enthalpy ($\Delta_i H_1$): The energy required to remove the first electron. A lower value indicates the metal can easily lose an electron, suggesting higher reactivity.
Second Ionisation Enthalpy ($\Delta_i H_2$): The energy required to remove the second electron. It is important for elements that can form ions with a +2 charge.
Electron Gain Enthalpy ($\Delta_{eg} H$): The energy change when an electron is added. This value impacts non-metal reactivity more; however, negative values (indicating a natural tendency to gain electrons) can still influence metal reactivity indirectly.

Let's analyze the given data:

Element	$\Delta_i H_1$ (kJ mol$^{-1}$)	$\Delta_i H_2$ (kJ mol$^{-1}$)	$\Delta_{eg}H$ (kJ mol$^{-1}$)
I	520	7300	-60
II	490	3051	-48
III	1681	3374	-328
IV	2372	5251	+48

Conclusion:

Element II has the lowest first ionisation enthalpy (490 kJ mol$^{-1}$), which means it can lose an electron more easily than the others.
The second ionisation enthalpy and electron gain enthalpy values of Element II indicate it can reasonably stabilize after losing an electron compared to others.

Therefore, the most reactive metal is Element II. This aligns with the correct answer option.

Observe the following data (\(\Delta_i H_1\), \(\Delta_i H_2\) and \(\Delta_{eg}H\) represent the first, second ionisation enthalpies and electron gain enthalpy respectively).

Using the data identify the most reactive metal.

Show Hint

The Correct Option is A

Solution and Explanation

Top Questions on Classification of elements and periodicity in properties

Questions Asked in TS EAMCET exam

Observe the following data (\(\Delta_i H_1\), \(\Delta_i H_2\) and \(\Delta_{eg}H\) represent the first, second ionisation enthalpies and electron gain enthalpy respectively). Using the data identify the most reactive metal.