Trend in Ionisation Enthalpy

Q.

The first ionization enthalpy values (in kJ $mo{l}^{–1}$ ) of group 13 elements are :



How would you explain this deviation from the general trend?

Q. The number of photons emitted by a monochromatic (single frequency) infrared range finder of power 1 mW and wavelength of 1000 nm, in 0.1 second is $x\times {10}^{13}.$ The value of x is . (Nearest integer)
($h=6.63\times {10}^{-34}Js,c=3.00\times {10}^{8}m{s}^{-1}$)

Q.

Why band gap of silicon is more than germanium?

Q.

M is a metal above hydrogen in the activity series and its oxide has the formula, M₂O. This oxide when dissolved in water forms the corresponding hydroxide which is a good conductor of electricity?

In the above context answer the following.

(i) What kind of combination exists between M and O?

(ii) How many electrons are there in the outermost shell of M?

(iii) Name the group to which M belongs.

(iv) State the reaction taking place at the cathode.

(v) Name the product at the anode.

Q.

The correct order of decreasing second ionisation enthalpy of Ti(22), V(23), Cr(24) and Mn(25) is [CBSE AIPMT 2008]

1. Cr > Mn > V > Ti

2. Mn > Cr > Ti > V

3. Ti > V > Cr > Mn

4. V > Mn > Cr > Ti

Q. The colour of $KMnO{{}_4}^{-}$ ion is due to :

1. d-d transition
2. Intravalence charge transfer
3. ligand to metal charge transfer
4. metal to ligand charge transfer

Q.

Amongst the elements with following electronic configurations, which one may have the highest ionisation energy? [CBSE AIPMT 2009]

1. $\left[Ar\right]3d^{10},4s^2,4p^3$

2. $\left[Ne\right]3s^{2}3p^3$

3. $\left[Ne\right]3s^{2}3p^2$

4. $\left[Ne\right]3s^{2}3p^1$

Q.

Which of the following electronic configuration of an atom has the lowest ionisation enthalpy? [CBSE AIPMT 2007]

1. $1s^2,2s^{2}2p^3$

2. $1s^2,2s^{2}2p^5$

3. $1s^2,2s^{2}2p^5,3s^1$

4. $1s^2,2s^{2}2p^6$

Q. The first ionisation energy of oxygen is less than that of nitrogen. Which of the following is the correct reason for this observation?

1. Lesser effective nuclear charge of oxygen than nitrogen
2. Due to stability of half-filled electronic configurations
3. Lesser atomic size of oxygen than nitrogen
4. Greater effective nuclear charge of oxygen than nitrogen

Q.

Nitrogen has positive electron gain enthalpy whereas oxygen has negative. However, oxygen has lower ionisation enthalpy than nitrogen. Explain.

Q.

How would you explain the fact that the first ionization enthalpy of sodium is lower than that of magnesium but its second ionization enthalpy is higher than that of magnesium?

Q. How to calculate radius ratio of TETRAHEDRAL void

Q.

The first ionization potential of $\mathrm{Na}$ is $5.1\mathrm{eV}$, the value of electron gain enthalpy of $\mathrm{Na}$ will be?

1. $-51\mathrm{eV}$

2. $-5.1\mathrm{eV}$

3. $-255\mathrm{eV}$

4. $-2.55\mathrm{eV}$

Q.

Among the second period elements the actual ionization enthalpies are in the order Li < B < Be < C < O < N < F < Ne. Explain why

(i) Be has higher ∆iH than B

(ii)O has lower $\Delta iH$ than N and F?

Q.

You are given that mass of ${\mathrm{Li}}_3^7=7.0160\mathrm{u}$, Mass of ${\mathrm{He}}_2^4=4.0026\mathrm{u}$ and mass of ${\mathrm{H}}_1^1=1.0079\mathrm{u}$. When $20\mathrm{g}\mathrm{of}{\mathrm{Li}}_3^7$ is converted into ${\mathrm{He}}_2^4$ by proton capture, the energy liberated, (in $\mathrm{kWh}$ ), is: [Mass of nucleon =$\frac{\mathrm{GeV}}{{\mathrm{c}}^2}$ ]

1. $6.82\times {10}^5$

2. $4.5\times {10}^5$

3. $8\times {10}^6$

4. $1.33\times {10}^6$

Q.

In the following question a statement of assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below in each question.
Boron has a smaller first ionisation enthalpy than beryllium.
Reason (R) The penetration of 2s electron to the nucleus is more than the 2p electron hence 2p electron is more shielded by the inner core of electrons than th e2s elelctrons.
(a) Assertion and reason both the correct statement but reson is not correct explanation for assertion.
(b) Assertion is correct statement but reason is wrong statement.
(c) Assertion and reason both are are corect statement and reason is correct eplanation for assertion.
(d) assertion and reason both are wrong statements

Q.

The energy of a photon is given as $3.03\times {10}^{-19}\mathrm{J}/\mathrm{atom}$. The wavelength of the photon is :

1. $6.56\mathrm{nm}$

2. $65.6\mathrm{nm}$

3. $0.656\mathrm{nm}$

4. $656\mathrm{nm}$

Q.

In the following question a statement of assertion (A) followed by a statement of Reason (R) is given. Choose the correct option out of the choices given below in each question.
Assertion (A) Generally, ionisation enthalpy increases from left to right in a period.
Reason (R) wehn quantum level, the shielding effect fo inner core of electrons does not increase very much to compensate for the increased attraction of the electron to the nucleus.
(a) Assertion is correct statement and reason is wrong statement.
(b) assertion and reason both are correct statements and reason is correct explanation of assertion.
(c) Assertion and reason both are wrong statements.
(d) Assertion is wrong statement and reason is correct statement.

Q.

Arrange the elements N, P O and S in the order of
(i) increasing first ionisation enthalpy.

(ii) Increasing non-metalic character. Give reason for the arrangement assigned.

Q.

Which of the elements has the greatest electron affinity among the halogens?

Q. The strongest reducing agent is
(1) Be
(2) Mg
(3) Sr
(4) Ba

Q.

Which electronic configuration of an element has abnormally high difference between $2^{nd}$ and $3^{rd}$ I.E.?

1. 1s², 2s², 2p⁶, 3s¹

2. 1s², 2s², 2p⁶, 3s², 3p¹

3. 1s², 2s², 2p⁶, 3s², 3p²

4. 1s², 2s², 2p⁶, 3s²

Q.

Why are lithium salts commonly hydrated and those of the other alkali metal ions usually anhydrous?

Q.

According to Werner's theory primary and secondary valency of [CoCl₃(NH₃)₃]Cl₃ is

Q.

Metallic character of elements decreases from left to right in a period while it increases while in moving down a group. Explain

Q.

Explain why is there a phenomenal decrease in ionisation enthalpy from carbon to silicon?

Q.

Sodium sulphate is soluble in water but barium sulphate is insoluble because

1. The hydration energy of Na₂SO₄ is more than its lattice energy

2. The lattice energy of BaSO₄ is more than its hydration energy

3. The lattice energy has no role to play in solubility

4. Both (a) and (b)

Q.

How does hydrogen differ from alkali metals?

Q.

What is the electron configuration of neon atom?

Q.

State the trend in chemical reactivity :

(ii) down the group.