Tag: chemistry

Questions Related to chemistry

Electronic configuration of silver atom in ground state.

chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

  1. $\left[ Kr \right] { 3d }^{ 10 }{ 4s }^{ 1 }$

  2. $\left[ Xe \right] { 4f }^{ 14 }{ 5d }^{ 10 }{ 6s }^{ 1 }$

  3. $\left[ Kr \right] { 4d }^{ 10 }{ 5s }^{ 1 }$

  4. $\left[ Kr \right] { 4d }^{ 9 }{ 5s }^{ 2 }$

Show answer
Correct Option: C
Explanation:

The electronic configuration of $Ag$ in ground state is:$[Kr]4d^{10}5s^1$

Write True or false:

The symbol of gold is Ag.

chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

  1. True

  2. False

Show answer
Correct Option: B
Explanation:

Symbol for gold is Au.

So, option-B is correct.

Neptunium is named after the: 

chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

  1. Planet Neptune

  2. Scientst Naptuna

  3. Place Naptunnom

  4. None of these

Show answer
Correct Option: A
Explanation:

Neptunium is named after the planet Neptune.

Tungsten is obtained from the latin name:

chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

  1. Wolfram

  2. Wolfire

  3. Wolfoam

  4. Wolfox

Show answer
Correct Option: A
Explanation:

The symbol for tungsten, W, comes from tungsten's Latin name Wolfram. The Latin name is derived from the tungsten mineral wolframite.


Hence, the correct option is $\text{A}$

Fill in the blanks 
Zero group elements are known as _________.

chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

  1. chalcogen

  2. inert gases

  3. halogens

  4. alkali metals

Show answer
Correct Option: B
Explanation:

The $'0'$ group elements have complete octate in outermost shell. As a result they have stable configuration due to which, they do not react with other elements. Hence they are known as inert gases.

An element $X$ belongs to fourth period and fifteenth group of the periodic table. Which of the following statements is true?

chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

  1. It has a completely filled s-orbital and a partially filled d-orbital.

  2. It has completely filled s-and p-orbitals and a partially filled d-orbital.

  3. It has completely filled s-and p-orbitals and a half-filled d-orbital.

  4. It has a half-filled p-orbital and completely filled s-and d-orbitals.

Show answer
Correct Option: D
Explanation:
Group 15 has a valence shell electronic configuration of $ns^2np^5$ and period $=4$$ means its $n=4$

thus electronic configuration of element $X$  is $4s^24p^3$

Elements of Group 15 and period 2 onwards are: $N, P, As, Sb, Bi$

Thus $X$ is Arsenic ($As$) and has electronic configuration of: $1s^22s^22p^63s^23p^63d^{10}4s^24p^3$. 

Thus, $s$ and $d-$orbitals are fully-filled and $p-$orbital is half-filled.

Hence, the correct option is $\text{D}$

Which of the following is an artificial element made by man?

chemistry the periodic table dobereiner's triads development of the modern periodic table into the history

  1. Gallium

  2. Iron

  3. Helium

  4. Americium

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Correct Option: D
Explanation:
In chemistry, a synthetic element is a chemical element that does not occur naturally on Earth, and can only be created artificially. So far, 24 synthetic elements have been created (those with atomic numbers 95–118). Americium is one of them having atomic no. 95.

Hence, the answer is option $D$.

Ethers have lower boiling points than their corresponding isomeric alcohols because of?

chemistry hydroxy compounds and ethers physical properties of ethers ethers alcohols, phenols and ethers

  1. hydrogen bonding in alcohols that is absent in ethers due to low polarity

  2. hydrogen bonding in ethers due to high polarity

  3. insolubility of ethers in water due to less polarity

  4. inertness of ethers as compared to alcohols.

Show answer
Correct Option: A
Explanation:

Ethers ROR cannot form intermolecular Hydrogen bond due to the absence of H attached with the electronegative atom as N/O/F, but in case of alcohols, they have -OH which can undergo intermolecular hydrogen bonding and that increases their boiling point.

Thus, Ethers have lower boiling points than their corresponding isomeric alcohols because of hydrogen bonding in alcohols that is absent in ethers due to low polarity.

Correct order of boiling points among following is: $\underset{(X)}{CH _3(CH _2) _3CH _3}, \,\,\,\,\underset{(Y)}{C _2H _5OC _2H _5},\,\,\,\,\,\,\underset{(Z)}{CH _3(CH _2) _3OH}$

chemistry hydroxy compounds and ethers physical properties of ethers ethers alcohols, phenols and ethers

  1. X > Y > Z

  2. Y > X > Z

  3. Z > X > Y

  4. Z > Y > X

Show answer
Correct Option: D
Explanation:

The boiling point of a molecule depends on the strength of intermolecular interaction such as Vandewaal's attraction, hydrogen bonding etc.

Alkanes, such as $\underset{X}{CH _3(CH _2) _3CH _3}$, being non-polar have the weakest force of attraction called dispersion or London forces.
Ethers, such as $\underset{(Y)}{C _{2}H _{5}OC _2H _5}$, have small dipole moment or weakly polar thus have dipole-dipole interaction. This is stronger than the London forces.
Alcohols, such as $\underset{(Z)}{CH _3(CH _2) _3OH}$, are polar molecules, therefore, have strong dipolar interaction. Moreover, they form an intermolecular hydrogen bond that further increases the attraction (association).

Hence the order of their boiling point will be:
$\underset{(Z)}{CH _3(CH _2) _3OH}>\underset{(Y)}{C _{2}H _{5}OC _2H _5}>\underset{X}{CH _3(CH _2) _3CH _3}$

OR $Z>Y>X$

The_____ ethers are highly volatile and flammable.

chemistry hydroxy compounds and ethers physical properties of ethers ethers alcohols, phenols and ethers

  1. higher

  2. lower

  3. both A and B

  4. None of these

Show answer
Correct Option: B