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The first ionzation enthalpies generally...

The first ionzation enthalpies generally increase form to right across the periodic table because of

A

increase of atomic size

B

increase of nuclear charge

C

increase of number of shilelding electrons

D

increase of effective nuclear charge

Text Solution

Verified by Experts

The correct Answer is:
D
By Coulomb's law, `F prop ((q^(+))(q^(-)))/(d^(2))`, the attraction for the outermost shell electrons is direvtly proportional to the effective charges and inversely proportional to the square of the distance between the charges. Since enegry is the produce of force and distance, the energy needed to remove an electron from teh outermost shell is proportional to the effective nuclear charge divided by the distance between electron and nucleus. This distance is inversely proportional to the effective nuclear charge.
`r_(n) = (n^(2)r_(1))/(Z_(eff)^(2))`
Hence, the ionization enthalpy is proportional to the square of the effective nuclear charge.
Due to the addition of electron in the same shell, the effective nuclear charge, `Z_(eff)`, increases going from left to right across a period. The increase in effective nuclear charge causes the outermost electrons to be held more tightly, making them harder to remove.
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In which of the following options order of arrangement does not agree with the variatioin of property indicated against it? Thinking process. i) The ionic size increases as the positive charge on the cation decreases or the negative charge on the anion increases. ii) First ionisation enthalpy increases from left to right in the periodic table. iii) Electron gain enthalpy increases as the electronegativity of the atom increases. iv) The metallic character increases as the size of the metal atom increases.

Metals are found on the right side of the periodic table.

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Why does the first ionisation energy increase as we go from left to right along a given period of periodic table?

The periodicity is related to the electronic configuration. That is, all chemical and physical properties are a manifestation of the electronic configuration of the elements. The atomic and ionic radii generally decrease in a period from left to right. As a consequence, the ionization enthalpies generally increase and electron gain enthalpies become more negative across a period. In other words, the ionization enthalpy of the exterme left element in a period is the least and teh electron gain enthalpy of the element on the exterme right is the highest negative. This results into high chemical reactivity at the two extermes and the lowest in he centre. Similarly down the group, the increase in atomic and ionic radii result in gradual decrease in ionization enthalpies and a regular decrease (with exception in some third period elements) in electron gain enthalpies in the case of main group elements. The loss and gain of electrons can be co-related with the reducting and oxidising behaviour, and also with metallic and non-metallic character respectively, of the elements. The correct order of the metallic character is:

The periodicity is related to the electronic configuration. That is, all chemical and physical properties are a manifestation of the electronic configuration of the elements. The atomic and ionic radii generally decrease in a period from left to right. As a consequence, the ionization enthalpies generally increase and electron gain enthalpies become more negative across a period. In other words, the ionization enthalpy of the exterme left element in a period is the least and teh electron gain enthalpy of the element on the exterme right is the highest negative. This results into high chemical reactivity at the two extermes and the lowest in he centre. Similarly down the group, the increase in atomic and ionic radii result in gradual decrease in ionization enthalpies and a regular decrease (with exception in some third period elements) in electron gain enthalpies in the case of main group elements. The loss and gain of electrons can be co-related with the reducting and oxidising behaviour, and also with metallic and non-metallic character respectively, of the elements. Which of the following statements is correct?

The periodicity is related to the electronic configuration. That is, all chemical and physical properties are a manifestation of the electronic configuratio of the elements. The atomic and ionic radii generally decrease in a period from left to right. As a consequence, the ionization enthalpes generally increase and electron gain enthalpies become more negative across a period. In order words, the ionization enthalpy of the extreme left element in a period is the least and the electron gain enthalpy of the element on the extreme right is the highest negative. This results into high chemical reactivity at the two extremes and the lowest in the centre. Similary, down the group, the increase in ionization enthalpies and a regular decrease (with exception in some third period elements) in electron gain enthalpies in the case of main group elements. The loss and gain of electrons can be co-related with the reducing and oxidising behaviour, and also with metallic and non-metallic character respectively of the elements. The correct order of the metallic character is:

The periodicity is related to the electronic configuration. That is, all chemical and physical properties are a manifestation of the electronic configuratio of the elements. The atomic and ionic radii generally decrease in a period from left to right. As a consequence, the ionization enthalpes generally increase and electron gain enthalpies become more negative across a period. In order words, the ionization enthalpy of the extreme left element in a period is the least and the electron gain enthalpy of the element on the extreme right is the highest negative. This results into high chemical reactivity at the two extremes and the lowest in the centre. Similary, down the group, the increase in ionization enthalpies and a regular decrease (with exception in some third period elements) in electron gain enthalpies in the case of main group elements. The loss and gain of electrons can be co-related with the reducing and oxidising behaviour, and also with metallic and non-metallic character respectively of the elements. The correct order of the non-metallic character is:

R SHARMA-CLASSIFICATION OF ELEMENTS AND PERIODICITY IN ELEMENTS-Follow-up Test
  1. In SI system, the ionizarion enthalpy is measured in

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  2. Ionization enthalpies are

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  3. The first ionzation enthalpies generally increase form to right across...

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  4. The largest ionization enthalpies in any period occur for the

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  5. The values of ionzation enthalpies tend to increase within each period...

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  6. Ionization enthalpies tend to decrease going down any column of main g...

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  7. Ionizarion is not limited to the removal of a single electron from an ...

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  8. Which of the following elements has a large jump between its fourth an...

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  9. Arrange the following elements in the order of incresing first ionizar...

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  10. The first four ionization enthalpies of an element are 578 kJ mol^(-1)...

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  11. Electron gain enthalpy of an element is a measure of its atom's abilit...

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  12. Which of the following is a measure of the firmness or strength with w...

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  13. Electron gain enthalpy is greater than zero for

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  14. Which of the following elements have the most negative electron gain e...

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  15. The general horizontal trend is that electron gain enthalpies become m...

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  16. Electron gain enthalpies of free anions are always

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  17. Which of the following elements has the most negative electron gain en...

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  18. Which of these elements has a less favorable (more positive) Delta(eg)...

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  19. Which of the noble gases has the maximum positive Delta(eg)H?

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  20. Which of the halogens has the largest negative Delta(eg)H?

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