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Why the first ionisation enthalphy of so...

Why the first ionisation enthalphy of sodium is lower than that of magnesium while its second ionisation enthlpy is higher than that of magnesium ?

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The "onization enthalpy of magnesium is higher than that of Na due to higher nuclear charge and slightly smaller atomic radius of Mg than Na. After the loss of first electron, Na formed has the electronic configuration of neon (2.8). The higher stability of the completely filled noble gas configuration leads to very high second ionization enthalpy for sodium. On the other hand, `Mg^+` formed after losing first electron still has one more electron in its outermost(s) orbital. As a result, the second ionization enthalpy of magnesium is much smaller than that of sodium
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FULL MARKS-PERIODIC CLASSIFICATION OF ELEMENTS -Textual Evaluation Solved( II brief question)
  1. Magnesium loses electrons successively to form Mg^(+),Mg^(2+)andMg^(3+...

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  2. Define electronegativity .

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  3. How would you explain the fact that the second ionisation potential is...

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  4. Energy of an electron in the ground state of the hydrogen atom is-2.18...

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  5. The electronic configuration of atom is one of the important factor wh...

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  6. In what period and group will an element with Z-118 will be present?

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  7. Justify that the fifth period of the periodic table should have 18 el...

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  8. Elements a,b,c and d have the following electronic configurations: ...

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  9. Give the general electronic configuration of lanthanides and actides?

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  10. Why halogens act as oxidising agents?

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  11. Mention any two anomalous properties of second period elements.

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  12. Explain the pauling method for the determination os ionic radius.

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  13. Explain the periodic trend of ionisation potential.

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  14. Explain the diagonal relationship

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  15. Why the first ionisation enthalphy of sodium is lower than that of mag...

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  16. Calculate the ionic radii of K^(+) and Cl^(-) ions in KCl crystal. T...

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  17. Explain the following, give appropriate reasons. (i) Ionization po...

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  18. What is screening effect ?

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  19. Briefly give the basis for pauling's scale of electronegativity.

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  20. State the trends in the variation of electronegativity in group and pe...

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