-
Engineering and Architecture
Exams
Colleges
Predictors
Resources
-
Computer Application and IT
Quick Links
Colleges
-
Pharmacy
Colleges
Resources
-
Hospitality and Tourism
Colleges
Resources
Diploma Colleges
-
Competition
Other Exams
Resources
-
School
Exams
Top Schools
Products & Resources
-
Study Abroad
Top Countries
Resources
-
Arts, Commerce & Sciences
Colleges
Upcoming Events
Resources
-
Management and Business Administration
Exams
Colleges & Courses
Predictors
-
Learn
Law Preparation
MBA Preparation
Engineering Preparation
Medical Preparation
-
Online Courses and Certifications
Top Streams
Specializations
- Digital Marketing Certification Courses
- Cyber Security Certification Courses
- Artificial Intelligence Certification Courses
- Business Analytics Certification Courses
- Data Science Certification Courses
- Cloud Computing Certification Courses
- Machine Learning Certification Courses
- View All Certification Courses
Resources
-
Medicine and Allied Sciences
Colleges
Predictors
Resources
-
Law
Resources
Colleges
-
Animation and Design
Exams
Predictors & Articles
Colleges
Resources
-
Media, Mass Communication and Journalism
Colleges
Resources
-
Finance & Accounts
Top Courses & Careers
Colleges
Electron Gain Enthalpy or Electron Affinity - (Concept)
Electron Gain Enthalpy
Electron gain enthalpy is the energy change that occurs when an electron is added to a neutral gaseous atom to form a negative ion. It is also known as electron affinity.
Factors affecting electron gain enthalpy
The electron gain enthalpy or electron affinity depends upon various factors such as:
-
Atomic Size
With the increase of atomic size, the distance between the nucleus and the last shell electrons also increases due to which the force of attraction between the nucleus and the incoming electron decreases. Hence, the electron gain enthalpy becomes less negative.
-
Nuclear Charge
With the increase of nuclear charge, the force of attraction between the nucleus and the incoming electron increases. Thus, the electron gain enthalpy becomes more negative.
-
Electronic Configuration
Elements that have half filled or completely filled orbitals are more stable than others. In these cases Generally, energy has to be provided to add an electron. Thus, their electron gain enthalpy generally has large positive values.
Variation of Electron Gain Enthalpy
-
The electron gain enthalpy becomes less negative in going from top to bottom in a group.
-
In moving from top to bottom in a group, both the atomic size and the nuclear charge increases. But the effect of the increase in atomic size is more dominant than the nuclear charge.
-
With the increase in atomic size, the attraction of the nucleus for the incoming electron decreases. Hence, the electron gain enthalpy becomes less negative. But in moving from left to right in a period, the attraction of the nucleus and the incoming electron increases and thus electron gain enthalpy becomes more negative.
-
Halogens have the most negative electron gain enthalpies. In moving down from chlorine to iodine, the electron gain enthalpies become less negative due to the increase in their atomic radii.
-
Chlorine has the most negative electron gain enthalpy value than fluorine. Because fluorine is very small in size due to which there is a very strong inter-electronic repulsion for the incoming electron, thus its electron gain enthalpy is less than chlorine.
-
Generally, Members of the 2nd period in p-block elements show the anomalous value of electron gain enthalpy.
Importance of Electron Gain Enthalpy
Some properties of the elements can be predicted on the basis of the electron gain enthalpy values.
-
The elements with high negative electron gain enthalpy values accept electrons easily and form ionic compounds. For example NaCl.
-
The elements with high negative electron gain enthalpy values are strong oxidising agents. For example, F, Cl, O.
-
Electrons affinity term was used for the gain of eletrons in older times, the use of which has been replaced by eletron gain enthalpy nowadays. It is generally defined as the negative of the electron gain enthalpy. Electron efficiency values for noble gases is however, defined to be zero. Other species like Be, Mg, Zn Cd, Hg, N etc. have positive values of eletrons affinity due to their half filled r fully filled orbital cinfiguraion.
| Exam | Chapter |
| JEE MAIN | Classification of Elements and Periodic table |
Which among the following factors is the most important in making fluorine the strongest oxidising agent?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
When the first electron gain enthalpy $\left(\Delta_{e g} H\right)$ of oxygen is -141kJ/mol , its second electron gain enthalpy is :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The order of increasing electron affinity of the electronic configurations is:
1)
2)
3)
4)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The correct order of electron affinity is :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Which one of the following arrangements represents correct order of electron gain enthalpy value (less negative) of the given atomic species?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
In which of the following arrangements, the order is not according to the property indicated against it?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Which one of the following statements is correct for the electron gain enthalpy of Ne & He?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Which one of the following arrangements shows the correct order of value of the given atomic species?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Choose the correct order of electron gain enthalpy or electron affinity among the following:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Electron affinity depends on:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The electron gain enthalpy(in kJ/mol) of fluorine, chlorine, bromine and iodine respectively are:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Within each pair of elements F and Cl, S and Se and Li and Na, respectively, the elements that release more energy upon an electron gain are
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The electronic configurations of four elements are given below: Arrange these elements in the correct order of the magnitude (without signs) of their electron gain enthalpy?
1)2s22p5
2)3s23p5
3)2s22p4
4)3s23p4
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The correct order of electron gain enthalpy is:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Increasing order of electron affinity is
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Electron affinity is the
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species.
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The formation of the oxide ion, from oxygen atom requires first an exothermic and then an endothermic step as shown below :
Thus process of formation of in gas phase is unfavourable even though
is isoelectronic with neon. It is due to the fact that
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The process that is NOT endothermic in nature is:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The correct order of electron gain enthalpies of Cl, F, Te and Po is
| A. |
|
| B. |
|
| C. |
|
| D. |
|
In which of the following pairs, electron gain enthalpies of constituent elements are nearly the same or identical ?
(A)
(B)
(C)
(D)
Choose the correct answer from the options given below :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Electron gain enthalpy with negative sign of fluorine is less than that of chlorine due to :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The electron gain enthalpies of halogens in kJ/mol are as given below.
The less negative value for as compared to that of
is due to :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Inert gases have positive electron gain enthalpy. Its correct order is
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The difference between electron gain enthalpies will be maximum between :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The correct sequence of electron gain enthalpy of the elements listed below is -
A. Ar B. Br C. F D. S
Choose the most appropriate from the options given below:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Given below are two statements:
Statement I : The correct order of first ionization enthalpy values of Li, Na, F and Cl is Na < Li < Cl < F.
Statement II : The correct order of negative electron gain enthalpy values of Li, Na, F and Cl is Na < Li < F < Cl
In the light of the above statements, choose the correct answer from the options given below :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Electronic configurations of four elements A, B, C, and D, are given below :
(A) $1 s^2 2 s^2 2 p^6$
(B) $1 s^2 2 s^2 2 p^4$
(C) $1 s^2 2 s^2 2 p^6 3 s^1$
(D) $1 s^2 2 s^2 2 p^5$
Which of the following is the correct order of increasing tendency to gain electrons?
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The correct group of isoelectronic species
| A. |
|
| B. |
|
| C. |
|
| D. |
|
An element ' $E$ ' has the ionisation enthalpy value of $374 \mathrm{~kJ} \mathrm{~mol}^{-1}$. 'E' reacts with elements A, B, C and D with electron gain enthalpy values of $-328,-349$, -325 and $-295 \mathrm{~kJ} \mathrm{~mol}^{-1}$, respectively.
The correct order of the products EA, EB, EC and ED in terms of ionic character is :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Among halogens, the correct order of amount of energy released in electron gain 3 (electron gain enthalpy) is:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The formation of the oxide ion, $O^{2-}(g)$, from oxygen atom requires first an exothermic and then an endothermic step as shown below: Thus process of formation of $O^{2-}$ in gas phase is unfavourable even though $O^{2-}$ is isoelectronic with neon. It is due to the fact that,
$\begin{aligned} & O(g)+e^{-} \rightarrow O^{-}(g) ; \Delta H^{\ominus}=-141 \mathrm{~kJ} \mathrm{~mol}^{-1} \\ & \mathrm{O}^{-}(\mathrm{g})+\mathrm{e}^{-} \rightarrow O^{2-}(\mathrm{g}) ; \Delta H^{\ominus}=+780 \mathrm{~kJ} \mathrm{~mol}^{-1}\end{aligned}$
| A. |
|
| B. |
|
| C. |
|
| D. |
|
The electron affinity value are negative for :
A. $\mathrm{Be} \rightarrow \mathrm{Be}^{-}$
B. $\mathrm{N} \rightarrow \mathrm{N}^{-}$
C. $\mathrm{O} \rightarrow \mathrm{O}^{2-}$
D. $\mathrm{Na} \rightarrow \mathrm{Na}^{-}$
E. $\mathrm{Al} \rightarrow \mathrm{Al}^{-}$
Choose the most appropriate answer from the options given below :
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Choose the correct statement:
| A. |
|
| B. |
|
| C. |
|
| D. |
|
Which of the following elements will gain one electron more readily in comparison to other elements of their group?
(i) S (g)
(ii) Na (g)
(iii) O (g)
(iv) Cl (g)
| A. |
|
| B. |
|
| C. |
|
| D. |
|
When an electron is added to a neutral gaseous atom (X) to convert it into a negative ion, the enthalpy change accompanying the process is defined as the Electron Gain Enthalpy ( ).
