Electron Affinity

Q. Arrange the following elements in the increasing order of their electron gain enthalpy.

1. Fluorine
2. Iodine
3. Chlorine
4. Bromine

Q.

Which of the following elements has the maximum electron affinity?

1. F

2. Cl

3. Br

4. I

Q. The second electron gain enthalpy for oxygen is .

1. positive
2. negative
3. zero

Q. ntThe work function of metal is 1 eV. Light of wavelength 3000 is incident on this metal surface. The velocity of emitted photo electrons will ben

Q.

Fluorine has the highest electronegativity among the $n{s}^{2}n{p}^5$ group on the Pauling scale, but the electron affinity of fluorine is less than that of chlorine because-

1. The atomic number of fluorine is less than that of chlorine.

2. Fluorine being the first member of the family behaves in an unusual manner.

3. Chlorine can accommodate an electron better than fluorine by utilizing its vacant 3d=orbital.

4. Small size, high electron density and an increased electron repulsion makes addition of an electron to fluorine less favourable than that in the case of chlorine.

Q.

Among halogens, the correct order of amount of energy released in electron gain is?

1. $\mathrm{F}>\mathrm{Cl}>\mathrm{Br}>\mathrm{I}$

2. $\mathrm{F}<\mathrm{Cl}>\mathrm{Br}>\mathrm{I}$

3. $\mathrm{F}>\mathrm{Br}>\mathrm{Cl}>\mathrm{I}$

4. $\mathrm{I}>\mathrm{Cl}>\mathrm{Br}>\mathrm{F}$

Q. Choose the options having correct order for electron gain enthalpy.

1. Cl > F > Br > I > Ar
2. F > Cl > Br > I > Ar
3. Ar > F > I > Br > Cl
4. Ar > Cl > Br > I > F

Q. Electron gain enthalpy of chlorine is than sulphur.

1. less negative
2. more negative
3. more positive

Q. 2nd seperation energy of an electron in H atom 1.27.2ev 2.1.57ev 3.3.4ev 4.13.6ev

Q. 7.Which of the following pairs of elements would have a higher electron gain enthalpy and why? (A) O, O- (B) F, Cl.

Q.

On moving across a period, the atomic size decreases and nuclear charge increases and therefore the force of attraction exerted by the nucleus on the electron in the outermost shell increases.
For the process
$A_{\left(g\right)}+e^{-}\to A_{\left(g\right)}^{-};\Delta H=xand{A}_{\left(g\right)}^{-}\to A_{\left(g\right)}+e^{-};\Delta H=y$
Select correct alternate:

1. Ionization energy of $A_{\left(g\right)}^{-}$ is y

2. Electron affinity of $A_{\left(g\right)}$ is x

3. Electron affinity of $A_{\left(g\right)}$ is -y

4. All are correct statements

Q.

Which of the following has the least electron affinity?

1. Silicon
2. Sulphur
3. Phosphorus
4. Chlorine

Q. Correct order of radius of the $1$st orbit of $H,{He}^{+},{Li}^{2+}$ and ${Be}^{3+}$ is:

1. $H>{He}^{+}>{Li}^{2+}>{Be}^{3+}$
2. ${Be}^{3+}>{Li}^{2+}>{He}^{+}>H$
3. ${He}^{+}>H>{Li}^{2+}>{Be}^{3+}$
4. ${He}^{+}>{Be}^{3+}>{Li}^{2+}>H$

Q.

The correct order of electron affinity is

1. N < Be > C < B

2. Be < B < C < N

3. N < Be < C < B

4. N < C < B < Be

Q.

$\text{Electron gain enthalpy}\alpha \frac{1}{\text{Atomic size}}$

1. True

2. False

Q.

The electron affinities of N, O, S, and Cl are such that

1. O ≈ Cl < N ≈ S

2. O < S < Cl < N

3. O < N < Cl < S

4. N < O < S < Cl

Q. Which element has highest positive value of electron gain enthalpy?

Q. Among the following elements, the removal of valence electrons from requires the maximum energy.

1. sodium
2. potassium
3. magnesium
4. fluorine

Q.

In each of the following sets, arrange the elements in the increasing order of their negative electron gain enthalpies: (i)C, N, O (ii)O, N, S (iii) Cl, S, Ar (iv)F, Cl, Br

Q. Why cl has more electron gain enthelpy than f? Electron gain enthelpy is inversily praportional to size, so f has smaller size than cl and electron gain enthelpy also decrease down the group.so f should have more electron gain enthelpy than cl electron gain enthelpy is amount of energy released or absorbed on addition of an electron, do due to smaller size the electron repulsion will be more in f so more amount of enrgy should be required by f to add an electron as compared to cl??

Q. An element in H atom in tis ground state absorbs 1.5times as much energy as the minimum required for ionisation of the atom.Thus KE of emitted electron is

Q. A. Give one word or a phrase for the following. [2 marks]
(i) The energy released when an electron is added to a neutral gaseous isolated atom to form a negatively charged ion.
(ii) The amount of any substance that contains $6.023\times {10}^{23}$ particles.

B. How will you distinguish between ammonium hydroxide and sodium hydroxide using copper sulphate solution? [2 Marks]

C. Give a reason for each of the following. [3 marks]
(i) Ionic compounds have a high melting point.
(ii) The blue colour of aqueous copper sulphate solution fades when it is electrolysed using platinum electrodes.
(iii) Conductivity of dilute hydrochloric acid is greater than that of acetic acid.

D. Arrange the following as per the the instruction given in the brackets: [3 marks]
(i) 50 cc of ${\text{SO}}_2$, 100 cc of ${\text{N}}_2$, 150 cc of ${\text{O}}_2$ (In increasing order of number of molecules at STP)
(ii) $K^{+},{\mathrm{Al}}^{3+},{\mathrm{Cu}}^{2+}$(In the increasing order of discharge at the cathode)
(iii) Na, K, Li (In the increasing order of atomic size)

Q.

Which one of the elements has the maximum electron affinity?

1. F

2. Cl

3. I

4. Br

Q. Addition of an electron is always an exothermic process.

1. False
2. True

Q.

"Generally, electron affinity values of elements decrease from top to bottom in a group of non metallic elements: However, elements of 2 period have lower electron affinity values than do the corresponding elements of 3rd period" Comment on this statement.

Q. Which of the following elements do not lose an electron easily?

1. Na
2. F
3. Mg
4. Cl

Q. Assertion :$M{g}^{2+}$ and $A{l}^{3+}$ are isoelectronic but ionic radius of $A{l}^{3+}$ is less than of $M{g}^{2+}$ Reason: The effective nuclear charge on the outershell electrons in $A{l}^{3+}$ is more than that in $M{g}^{2+}$

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Assertion is incorrect but Reason is correct

Q. Assertion :$M{g}^{2+}$ and $A{l}^{3+}$ are isoelectronic but ionic radius of $A{l}^{3+}$ is less than that of $M{g}^{2+}$. Reason: The effective nuclear cahrge on the outershell electrons in $A{l}^{3+}$ is more than that in $M{g}^{2+}$.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Assertion :${Na}^{+}$ and ${Al}^{3+}$ are isoelectronic but the magnitude of ionic radius of ${Al}^{3+}$ is less than that of ${Na}^{+}$. Reason: The magnitude of effective nuclear charge of the outer shell electrons in ${Al}^{3+}$ is greater than in ${Na}^{+}$.

1. Assertion and reason both are correct statements and reason is correct explanation for assertion.
2. Assertion and reason both are correct statements but reason is not correct explanation for assertion.
   
3. Assertion is correct statement but reason is wrong statement.
4. Assertion is wrong statement but reason is correct statement.

Q. Atomic size of fluorine is smaller than chlorine and electron gain enthalpy is inversely proportional to atomic size .So, why electron gain enthalpy of chlorine is more than fluorine?