Tag: group 17 elements - properties

Questions Related to group 17 elements - properties

$PbI _4$ does not exist because :

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. iodine is not a reactive

  2. $Pb(IV)$ is oxidizing and $I^-$ is strong reducing agent

  3. $Pb(IV)$ is less stable than $Pb(II)$

  4. $Pb^{4+}$ is not easily formed

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Correct Option: C

Halogens have:

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. high ionisation energies

  2. high electronegativities

  3. high electron affinities

  4. All the above

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Correct Option: D
Explanation:

Halogens have high ionisation energies, high electronegativities and high electron affilities due to their smallest size in a particular period. As size decreases ionisation energy, elctronegativity and electron affinity increaes

Iodine is more soluble in aqueous solution of Kl because it forms soluble :

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. $\mathrm{K}\mathrm{I} _{2}$

  2. $\mathrm{K}\mathrm{I} _{3}$

  3. $\mathrm{K}\mathrm{I} _{4}$

  4. $\mathrm{K} _{2}I _{2}$

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Correct Option: B
Explanation:

$KI+I _2\rightarrow KI _3$ soluble 
$\therefore $ Iodine is more soluble in KI (aq)

Iodine dissolves in aqueous Kl due to the formation of:

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. $I^{-}$

  2. $ I _{2}^{-}$

  3. $ I _{3}^{-}$

  4. $I _{4}^{-}$

Show answer
Correct Option: C
Explanation:

$KI\ (aq)\rightarrow K^{(+)}+I^-$

$I _2+I^-\rightarrow I _3 ^-$
$\therefore$ Iodine dissolves in KI (aq) due to the formation of $I _{3}^{-}$ ion.

In the reaction of $I _{2}$ with water, change in free energy is:

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. negative

  2. positive

  3. zero

  4. Can't be predicted

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Correct Option: B
Explanation:

The reaction of $I _2$ with water is endothermic 
so, change in free energy is Positive.

_______ is the only member of the halogen family that has no stable isotopes.

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. $\displaystyle F$

  2. $\displaystyle Cl$

  3. $\displaystyle Br$

  4. $\displaystyle I$

  5. $\displaystyle At$

Show answer
Correct Option: E
Explanation:

Astatine has many isotopes, all of which are radioactive in nature. Their half-lives are also very small. Hence, astatine has no stable isotopes.

Option $E$ is the correct answer.

Volatile nature of halogens is because:

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. halogen molecules are bonded by strong forces

  2. halogen molecules are bonded by electrostatic forces

  3. the forces existing between the discrete molecules are only weak Van der Waals forces

  4. halogen molecules are more reactive

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Correct Option: C
Explanation:

Van der Waals force- It is a general term used to define the attraction of intermolecular forces between molecules.

Van der Waals force $\propto$ Molecular weight
As you go down the group, halogens become less volatile, as their shell size increases. This increases the Van der Waals forces as there are more electrons, hence increasing the force of attraction between molecules. This makes them less volatile.

The element with highest electron affinity among the halogens is :

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. F

  2. $Cl$

  3. Br

  4. $I$

Show answer
Correct Option: B
Explanation:

As moving down the group electron affinity of elements decreases

But in case of $\textbf{Fluorine}$, it is a small atom with a small amount of space available in its 2p orbital. Because of this, any new electron trying to attach to fluorine experiences lower electron affinity from the electrons already living in the element's 2p orbital. Since chlorine's outermost orbital is a 3p orbital, there is more space, and the electrons in this orbital are inclined to share this space with an extra electron. Therefore, chlorine has a higher electron affinity than fluorine, and this orbital structure causes it to have the highest electron affinity of all of the elements.

Hence electron affinity of $\textbf{Chlorine}$ is higher in halogens.

Chlorine displaces the following from their salts :

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. Fluorine

  2. Nitrogen

  3. Bromine

  4. Iodine

Show answer
Correct Option: C,D
Explanation:

Chlorine displaces Bromines and Iodine from their salts as chlorine is more electronegative than bromine and iodine.
$2KBr+Cl _2\rightarrow 2KCl+Br _2$
$2KI+Cl _2\rightarrow 2KCl+I _2$

Which one of the following halogen liberates oxygen on reacting with $H _2O$ ?

group 17 elements - trends in chemical properties group 17 elements - properties p- block elements-ii p-block elements chemistry

  1. $I _2$

  2. $Cl _2$

  3. $Br _2$

  4. $F _2$

Show answer
Correct Option: D
Explanation:

Reaction of $F _2$ and $H _2O$-

$F _2 + H _2O \longrightarrow 2HF + \dfrac{1}{2}O _2$
So $F _2$ liberates oxygen on reacting with $H _2O$