Tag: atomic theory, periodic classification and properties of elements

Questions Related to atomic theory, periodic classification and properties of elements

Catalyst in a reaction:

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. lower the activation energy

  2. increases the activation energy

  3. increases the rate of reaction

  4. both A and C

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Correct Option: D

A biological catalyst is

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1.  $N _2$ molecules

  2. an enzyme

  3. an amino acid

  4. a carbohydrate

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Correct Option: B

Transition elements are also known as ____________.

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. $d$ - block elements

  2. $f$ - block elements

  3. $s$ - block elements

  4. None of these

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Correct Option: A
Explanation:

The transition elements are also known as the $d$-block elements because while the outermost level contains at most two electrons, their next to outermost main levels have incompletely filled $d$ sub-orbitals, which are filled-up progressively ongoing across the periodic table from $8$ to $18$ electrons. The filling of the $d$ sub-orbitals of the transition elements across a row of the periodic table is not always regular.


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

A metal crystallizes with a face-centred cubic lattice. The edge length of the unit cell is 408 pm. The diameter of the metal atom is:

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. 228 pm

  2. 288 pm

  3. 144 pm

  4. 326 pm

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Correct Option: B

Hydrolysis of urea is an example of

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. Homogenious reaction

  2. heterogenious reaction

  3. Biomolecular reaction

  4. Both a and b

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Correct Option: C
Explanation:

Enzymes are biological catalysts which catalyze the biochemical reactions in living organisms.

Hydrolysis of urea by urease is an example of  biochemical catalysis.

 

Predict block, group and period of $Sb$.

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. Block-$p$, Period-$5$, Group-$15$

  2. Block-$p$, Period-$5$, Group-$14$

  3. Block-$s$, Period-$5$, Group-$13$

  4. Block-$s$, Period-$5$, Group-$11$

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Correct Option: A
Explanation:

Antimony is a chemical element with symbol $Sb$ (from Latin: stibium) and atomic number $51$,group $15$ (pnictogens), $p$-block,period $5$.

Based on modern classification of periodic table atomic number increases on moving from _________ in periodic table.

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. left to right

  2. right to left

  3. straight

  4. none of these

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Correct Option: A
Explanation:

Elements in the same period tend to have shared chemistry and exhibit a  trend in properties with increasing atomic number from left to right.

The modern periodic table is most_________ form of periodic table.

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. insignificant

  2. Significant

  3. Both A and B

  4. None of these

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Correct Option: B
Explanation:

In the standard periodic table, the elements are listed in order of increasing atomic number. Thus, it is relatively easy to predict the chemical properties of an element if one knows the properties of the elements around it i.e. it is more significant form of periodic table.

Significance of classification of periodic table is to ___________.

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. predict the blocks of elements

  2. predicts the groups of elements

  3. both A and B

  4. none of these

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Correct Option: C
Explanation:

Periodic classification of elements is the method by which elements are grouped on the basis of their characteristics. Classification of elements in groups provide us a fixed pattern in which the elements change their properties periodically. Periodic table made the study of physical and chemical properties of elements simple and organized.

Alkali and alkaline earth metals are ________ elements.

chemistry atomic theory, periodic classification and properties of elements introduction to periodic table necessity of classification need for classification

  1. same

  2. different

  3. both A and B

  4. none of these

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Correct Option: B
Explanation:

Alkali and alkaline earth metals are group I and group II elements of s block representative elements with ns$^1$ and ns$^2$ valence shell configuration respectively.


Hence, option B is correct.