Tag: classification of elements- the periodic table

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Questions Related to classification of elements- the periodic table

Multiple choice chemistry classification of elements- the periodic table periodic trends in physical properties properties and trend trends in periodic table electronic configuration and valency electron configuration

Define the relation among the $EN,\,IE\;and\;E.A.$

  1. $EN=\displaystyle\frac{IE\times EA}{2}$
  2. $EN=IE+EA$
  3. $2EN=IE-EA$
  4. $EN=\displaystyle\frac{IE+EA}{2}$
  5. $EN=\displaystyle\frac{IE-EA}{2}$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The correct relationship is $EN = \dfrac {IE+EA}{2}$
According to mulliken's scale, the electronegatiity is the average value of ionization potential and electron affinity of an atom.

Multiple choice chemistry classification of elements- the periodic table periodic trends in physical properties properties and trend trends in periodic table electronic configuration and valency electron configuration

An element $X$ has $IP = 1681$ kJ/mole and $EA =-333$ kJ/mole then its electronegativity is:

  1. $(1681 + 333) / 544$
  2. $(1681 - 333 )/ 544$
  3. $(1681 + (-333)) / 2$
  4. $\dfrac{208\sqrt{1681+333}}{544}$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Robert S. Mulliken proposed that the arithmetic mean of the first ionization energy ($E i$) and the electron affinity ($E _{ea}$) should be a measure of the tendency of an atom to attract electrons. As this definition is not dependent on an arbitrary relative scale, it has also been termed absolute electronegativity, with the units of kilojoules per mole or electron volts.
                                        <img src="https://wikimedia.org/api/rest_v1/media/math/render/svg/44e7db9c2cb1be249c807e9435c4d11788ea2efc" class="mwe-math-fallback-image-inline" alt="\chi =(E{\rm {i}}+E_{\rm {ea}})/2\,">

Multiple choice chemistry classification of elements- the periodic table periodic trends in physical properties properties and trend trends in periodic table electronic configuration and valency electron configuration

The ${ Z } { eff }$ for
3d electron of Cr
4s electron of Cr
3d electron of ${ Cr }^{ 3+ }$
3s electron of ${ Cr }^{ 3+ }$ are _________ respectively.

  1. 4.6, 2.95, 4.95, 8.05

  2. 4.95, 2.05, 4.6, 8.05

  3. 4.6, 2.95, 5.3, 12.75

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

Cr ${ 1s }^{ 2 }\quad { 2s }^{ 2 }\quad { 2p }^{ 6 }\quad { 3s }^{ 2 }\quad { 3p }^{ 6 }\quad { 3d }^{ 5 }\quad { 4s }^{ 1 }$

${ 24 }^{ - }$
Using later's rule:
for $3de^{ - }\quad { Z } _{ eff }=24-(4\times 0.35)-(18\times 1)=4.6$
for $4se^{ - }\quad { Z } _{ eff }=24-(0\times 0.35)-(13\times 0.85)-(10\times 1)=2.95$
$Cr^{ 3+ }\quad ({ 1s }^{ 2 }\quad { 2s }^{ 2 }\quad { 2p }^{ 6 }\quad { 3s }^{ 2 }\quad { 3p }^{ 6 }\quad { 3d }^{ 3 })$
for $3de^{ - }\quad { Z } _{ eff }=24-(2\times 0.85)-18=5.3$
for $3se^{ - }\quad { Z } _{ eff }=24-(7\times 0.35)-(8\times 0.85)-(2\times 1)=12.75$
                                         ${ s }^{ 1 }p^{ 6 }$           $2({ s }^{ 2 }p^{ 6 })$                    ${ 1s }^{ 2 }$

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

The elements posses stable electronic configuration are called as __________.

  1. Transition metals

  2. Non-transition metals

  3. Noble gases

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

Noble gases have stable configuration of $ns^2 np^6$ with their octet completely filled which, gives them stability. Helium has exception.

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

According to classification of elements most of non-metals are placed in ________ block.

  1. $s$ - block
  2. $p$ - block
  3. $d$ - block
  4. $f$ - block
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The $p$ - block is the area of the periodic table containing columns $3A$ to column $8A$ (columns$ 13-18$), including noble gas, all non metals, metals and metalloids. 

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

After the classification of elements study of elements become____________.

  1. difficult

  2. easy

  3. both A and B

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

 Elements with similar chemical properties generally fall into the same group in the periodic table, and the elements in the same period tend to have similar properties.Thus, it is relatively easy to predict the chemical properties of an element if one knows the properties of the elements around it.

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

Classification of elements are done on the basis of ___________.

  1. atomic number

  2. atomic weight

  3. valency

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

Based on the modern periodic law, the elements are arranged into rows and columns based on their atomic number. There are 18 columns, called groups and 7 rows, called periods. 

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

The physical properties of elements changes according to_____________.

  1. classification of elements in groups and periods

  2. classification of elements in groups

  3. classification of elements in periods

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

The physical properties (notably, melting and boiling points) of the elements in a given trend in vary from group to group and from period to period.


Hence the correct option is A.