Selected second-ionization-energy ( ) values are shown for two adjacent Period 3 elements

CHEMISTRY · Multi-part · A Level · Chemistry · Atomic structure · Atomic structure

Problem

Selected second-ionization-energy (

I_2

) values are shown for two adjacent Period 3 elements.

Element	$I_2$ (kJ mol $^{-1}$ )
Na	4560
Mg	1450

(1) Write the full electron configurations of (i) Na

^{+}

and (ii) Mg

^{+}

prior to removal of the second electron. (2) Using your configurations, explain in detail why

I_2

for Na is substantially larger than

I_2

for Mg. (3) Predict whether the difference between

I_2

values for Al and Si will be greater than, less than, or approximately equal to the difference observed between Na and Mg. Support your prediction with atomic-level reasoning.

Related theory

Electronic Configuration
Atomic Structure
Structure of Atom
Electron configurations

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