MCQ
Correct increasing order of first ionistion potential is
- ✓$Na < Mg > Al < Si$
- B$Na < Mg < Al < Si$
- C$Na > Mg > Al > Si$
- D$Na < Mg < Al > Si$
✓
Answer
Correct option: A.
$Na < Mg > Al < Si$
a
As we move across the period, nuclear charge increases, atomic size decreases hence, ionization enthalpy increases. For $Al \left(3 s ^2\, 3 p ^1\right)$, electron has to be removed from partially filled $3 p$ orbital whereas in $Mg \left(3 s ^2\right)$, electron has to be removed from stable fully filled $3 s$ orbital.
As we move across the period, nuclear charge increases, atomic size decreases hence, ionization enthalpy increases. For $Al \left(3 s ^2\, 3 p ^1\right)$, electron has to be removed from partially filled $3 p$ orbital whereas in $Mg \left(3 s ^2\right)$, electron has to be removed from stable fully filled $3 s$ orbital.
Removal of an electron from stable, fully filled orbital requires more energy than removal of electron from partially filled orbital. Thus, ionisation enthalpy for $Mg$ is greater than ionisation enthalpy for $Al$. So, the correct order of first ionization enthalpies is: $Na \,<\, Mg\, >\, Al\, <\, Si$
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
an oxidation-reduction reaction in which $3$ electrons are transferred has a $\Delta G ^{\circ}$ of $17.37\, kJ$ $mol ^{-1}$ at $25^{\circ} C$. The value of $E _{\text {cell }}^{\circ}$ (in $V$ ) is........ $\times 10^{-2}$
→$\left(1 F =96,500\, C\, mol ^{-1}\right)$
In which of the following reaction conc. $H_2SO_4$ is acts as an oxidising agent?
→The addition of $\ce{HCl}$ will not suppress the ionisation of :
→In which of the process entropy increases
→$(a)\,B{r_2}(l) \to B{r_2}(g)$
$(b)\,{H_2}O(s) \to {H_2}O(g)$
$(c)\,{N_2}\,\left[ {1\,atm,\,{{100}\,^o}C} \right] \to {N_2}\,\left[ {1\,atm,\,{{150}\,^o}C} \right]$
$(d)\,{N_2}\,(g) + 3{H_2}(g) \to 2N{H_3}(g)$
$(e)\,CaC{O_3}(s) \to CaO(s) + C{O_2}(g)$
Product $(A)$ is
→Which of the following is not correctly matched
Bromination of alkanes involves
Which is polymeric hydride?
Oxidation number of sulphur in ${S_2}O_3^{2 - }$is
→Which of the following is a Lewis base