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QJEEM21Ch3c8e: JEE Main 2021 Chemistry - Class 11 JEEM21Ch3c8e Solution: Identify the elements X and Y using the ionisation energy…

Identify the elements X and Y using the ionisation energy values given below :

Ionization energy (kJ/mol)
1 st{st} 2 nd{nd}
X 495 4563
Y 731 1450

Multiple Choice Options

  • A X = F; Y = Mg
  • B X = Mg; Y = F
  • C X = Na; Y = Mg
  • D X = Mg; Y = Na

Step-by-Step Verified Solution

Due to 2p6, noble gas electronic configuration, the second ionisation enthalpy of Na is very high. That’s why has large difference between IE1, and IE2

Mg+ is 2p6, 3s1.

After the loss of one electron, Mg+ will be formed with noble gas electronic configuration. That’s why has less difference between I.E1 and I.E2, but it's I.E3 is very high.

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