Atomic Radii and Ionization Energy (Group 1)

Q.

Does effective nuclear charge increase across and down the group?

No....... Is it correct?

Q. The correct order of stability of hydrides of alkali metals is:

1. $NaH>KH>RbH>LiH$
2. $RbH>KH>NaH>LiH$
3. $LiH>NaH>KH>RbH$
4. $LiH>RbH>KH>NaH$

Q.

The order of decreasing ionisation enthalpy in alkali metals is
(a) Na> Li > K> Rb (b) Rb< Na< K< Li
(c) Li > Na> K> Rb (d) K< Li < Na < Rb

Q.

As compared to potassium, sodium has

1. Lower electronegativity

2. Higher ionization potential

3. Greater atomic radius

4. Lower melting point

Q.

The ionic radii of alkali metal ions in water (hydrated radii) are in the order

1. Li+> Na+> K+>Rb+< Cs+

2. LI+< Na+> K+>Rb+> Cs+

3. Li+ (aq.) > Na+ (aq.) < K+ (aq.) <Rb+ (aq.) < Cs+ (aq.)

4. Li⁺ (aq.) > Na+ (aq.) > K+ (aq.) >Rb+ (aq.) > Cs+ (aq.)

Q. Which of the following(s) represent the correct order of first ionisation energy of d-block elements?

1. $Sc>Y>La$
2. $Cd<Zn<Hg$
3. $Pd<Ni<Pt$
4. Both (a) and (b)

Q. $NaH$ is an example of:

1. Electron-rich hydride
2. Molecular hydride
3. Saline hydride
4. Metallic hydride

Q. Which of the following factor may be regarded as the main cause of lanthanide contraction?

1. Poor shielding of $4f$- electrons as compared to other electrons
2. Effective shielding of one of the $4f$ electrons as compared to other electrons
3. Poorer shielding of $5d$ electron by $4f$ - electrons
4. Greater shielding of $5d$ electron by $4f$ - electron

Q. The stability of inter halogen compound follows the order

1. > >
2. > >
3. > >
4. > >

Q. The charge/size ratio of a cation determines its polarizing power. Which one of the following sequences represents the increasing order of the polarizing power of the cationic species, $K^{+},C{a}^{2+},M{g}^{2+},B{e}^{2+}$

1. $K^{+}>C{a}^{2+}>M{g}^{2+}<B{e}^{2+}$
2. $B{e}^{2+}<C{a}^{2+}<M{g}^{2+}<K^{+}$
3. $M{g}^{2+}<K^{+}<B{e}^{2+}<C{a}^{2+}$
4. $K^{+}<C{a}^{2+}<M{g}^{2+}<B{e}^{2+}$

Q.

Arrange the following elements in increasing order of their atomic radii. (b) $\mathrm{Cl},\mathrm{At},\mathrm{Br},\mathrm{I}$

Q.

The ionic radius of the ions having same charge of d block elements in a given series:

1. Increases from left to right across a period

2. Decreases from left to right across a period

3. First increases then decreases

4. Remains constant throughout

Q. Identify the incorrect statement among the following.

1. Lanthanide contraction is the accumulation of successive shrinkages
2. As a result of Lanthanide contraction, the size of $4d$ series of transition metals have same size that of the $5d$ series of elements of same group
3. Ionization energy of 4d series elements is higher than corresponding 5d series elements of same group
4. Lanthanide contraction is the cause of lower ionisation energy of $Sn$ than $Pb$

Q.

(i) The energy associated with the first orbit in the hydrogen atom is –2.18 × 10^–18 J atom^–1. What is the energy associated with the fifth orbit?

(ii) Calculate the radius of Bohr’s fifth orbit for hydrogen atom.

Q. Lanthanoid ions shows:

1. Magnetic properties
2. Colour and spectral properties
3. Lanthanide contraction
4. All of these

Q. In the complexes $\left[Fe\right(H_{2}O{)}_6{]}^{3+},\left[Fe\right(CN{)}_6{]}^{3-},\left[Fe\right(C_2{O}_4{)}_3{]}^{3-}$ and $[FeC{l}_6{]}^{3-}$, more stability is shown by :

1. $\left[Fe\right(CN{)}_6{]}^{3-}$
2. $\left[Fe\right(H_{2}O{)}_6{]}^{3+}$
3. $[FeC{l}_6{]}^{3-}$
4. $\left[Fe\right(C_2{O}_4{]}^{3-}$

Q. The lanthanide contraction is responsible for the fact that:

1. $Zr$ and $Hf$ have about the same radius
2. $Zr$ and $Zn$ have the same oxidation state
3. $Zr$ and $Y$ have about the same radius
4. $Zr$ and $Nb$ have similar oxidation state

Q. Why ionic radii of Cu2+ is less than Zn2+, Although atomic radius decreases across a period?

Q. As we go down the group the atomic radius increases.

1. False

2. True

Q. How number of electrons affect the effective nuclear charge and ionic radius?

Q.

Which element has the highest electronegativity

1. Mg

2. C

3. O

4. S

Q. Because of lanthanoid contraction, which of the following pairs of elements have nearly the same atomic radii?

1. $Zr$ (40) and $Hf$ (72)
2. $Zr$ (40) and $Ta$ (73)
3. $Ti$ (22) and $Zr$ (40)
4. $Zr$ (40) and $Nb$ (41)

Q. Why do the transition elements exhibit higher entalpies of atomisation ?

Q. $ZnO$ is white when cold and is yellow when hot. What is the reason behind this colour change?

Q. Consider following statements.
$\left(I\right)$ The size of the lanthanide ions $\left(M^{3+}\right)$ decreases as the atomic number of $M$ increases.
$\left(II\right)$ Electronic spectra of lanthanides show very broad bands.
$\left(III\right)$ As with transition metals, coordination number six is very common in lanthanide complexes.
Which of the statements given above is/are correct?

1. $I$ only
2. $III$ only
3. $I$ and $II$
4. $I$ and $III$

Q. Assertion :$BeS{O}_4$ and $MgS{O}_4$ are insoluble in water. Reason: $B{e}^{2+}$ and $M{g}^{2+}$ have low hydration enthalpies.

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. Choose the correct order of the following :

1. $N-H>P-H>As-H>Sb-H\text{: Polarity order}$
   
2. $M{g}^{2+}\left(aq\right)>S{r}^{2+}\left(aq\right)>B{a}^{2+}\left(aq\right)\text{: Hydrated radius order}$
   
3. $M{g}^{2+}\left(aq\right)>S{r}^{2+}\left(aq\right)>B{a}^{2+}\left(aq\right)\text{Ionic mobility order}$
4. $NaF>MgO>SrO\text{: Lattice energy order}$

Q. In $A^{+}{B}^{-}$ ionic compound, radii of $A^{+}$ and $B^{-}$ ions are $180pm$ and $187pm$ respectively. The crystal structure of this compound will be:

1. $NaCl$ type
2. $Zns$ type
3. $CsCl$ type
4. Similar to diamond

Q. The atomic radii of the group IA element's decreases as we go down the group.

1. True

2. False

Q. Select the correct options:

1. Due to lanthanide contraction $Zr$ and $Hf$ have almost equal size.
2. $d$- and $f$-orbitals do not shield the nuclear charge very effectively.
3. Both (A) & (B) are correct statements.
4. Both (A) & (B) are incorrect statements.