The first ionization enthalpies of Na, Mg and | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) $Na, Mg, Al$ and $Si$ belong to the $3^{rd}$ period of the periodic table.Generally,the first ionization enthalpy increases across a period due to

Vedclass · Accepted Answer

$575$

Vedclass · Answer

(C) $Na, Mg, Al$ and $Si$ belong to the $3^{rd}$ period of the periodic table.Generally,the first ionization enthalpy increases across a period due to an increase in effective nuclear charge.However,$Mg$ $(3s^2)$ has a fully-filled $s$-orbital,making it more stable than $Al$ $(3s^2 3p^1)$.Therefore,the first ionization enthalpy of $Al$ is lower than that of $Mg$ but higher than that of $Na$.Given values: $Na = 496 \ kJ \ mol^{-1}$,$Mg = 737 \ kJ \ mol^{-1}$,$Si = 786 \ kJ \ mol^{-1}$.The value for $Al$ must be between $496$ and $737 \ kJ \ mol^{-1}$.Thus,the correct value is $575 \ kJ \ mol^{-1}$.

Element	$IE_1$	$IE_2$	$IE_3$
$P$	$495.8$	$4562$	$6910$
$Q$	$737.7$	$1451$	$7733$
$R$	$577.5$	$1817$	$2745$

The first ionization enthalpies of $Na, Mg$ and $Si$ are respectively $496, 737$ and $786 \ kJ \ mol^{-1}$. What would be the first ionization enthalpy of $Al$ in $kJ \ mol^{-1}$?

Similar Questions

The first three ionisation energies (in $kJ/mol$) of three representative elements are given below:

Element $IE_1$ $IE_2$ $IE_3$

$P$ $495.8$ $4562$ $6910$

$Q$ $737.7$ $1451$ $7733$

$R$ $577.5$ $1817$ $2745$

Which of the following options is incorrect?

The first four ionisation energy values of an element are $191$,$578$,$872$ and $5962 \ kcal$. The number of valence electrons in the element is :-

Which particle may be removed from a stable neutral atom with the least energy change?

The order of ionisation potential between $He^{+}$ ion and $H$ atom (both species are in gaseous state) is

As compared to potassium,sodium has

Vedclass Test Series

Exam Paper Generator

Online Exam Module