Tag: necessity of classification

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

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:

  1. 228 pm

  2. 288 pm

  3. 144 pm

  4. 326 pm
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a face-centered cubic (FCC) lattice, the relation between edge length (a) and atomic radius (r) is a = 2 * sqrt(2) * r. The diameter (d) is 2r. Thus, d = a / sqrt(2). Given a = 408 pm, d = 408 / 1.414 = 288.5 pm, which rounds to 288 pm.

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

Hydrolysis of urea is an example of

  1. Homogenious reaction

  2. heterogenious reaction

  3. Biomolecular reaction

  4. Both a and b
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

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

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

 

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

Predict block, group and period of $Sb$.

  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-$11$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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

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

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

  1. left to right

  2. right to left

  3. straight

  4. none of these
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

The modern periodic table is most_________ form of periodic table.

  1. insignificant

  2. Significant

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

Significance of classification of periodic table is to ___________.

  1. predict the blocks of elements

  2. predicts the groups of elements

  3. both A and B

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

Multiple choice chemistry classification of elements- the periodic table introduction to periodic table necessity of classification need for classification

Classification of periodic table based on atomic number is given by:

  1. Mendeleev's

  2. Mosley

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Henry Moseley found a relationship between the X-ray wavelength of an element and its atomic number. Moseley's discovery showed that atomic numbers were in fact based upon experimental measurements.

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

Alkali and alkaline earth metals are ________ elements.

  1. same

  2. different

  3. both A and B

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
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.

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

Lanthanoids are also called as ___________.

  1. Transition elements

  2. Rare earth elements

  3. Both A and B

  4. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Rare earth metals are a group of chemically similar metallic elements comprising the lanthanide series and (usually) scandium and yttrium. They are not especially rare, but they tend to occur together in nature and are difficult to separate from one another.