Tag: need for classification

Questions Related to need for classification

In laboratory burners, we use

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

  1. Producer gas

  2. Oil gas

  3. Gobar Gas

  4. None of the above

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Correct Option: B
Explanation:

In laboratory burners , oil gas is generally used oil gas is mixture of $CH _4 + CO + CO _2 + H _2$

Hence, the correct option is B

Who was the first to classify the elements into metals and non-metals?

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

  1. Meyer

  2. Mendeleev

  3. Lavoisier

  4. None of the above

Show answer
Correct Option: C
Explanation:

Lavioser was the first person to classify elements into metals and non metal. The concept of metalloids came in later

The elements posses stable electronic configuration are called as __________.

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

  1. Transition metals

  2. Non-transition metals

  3. Noble gases

  4. None of these

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Correct Option: C
Explanation:

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

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

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

  1. $s$ - block

  2. $p$ - block

  3. $d$ - block

  4. $f$ - block

Show answer
Correct Option: B
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. 

After the classification of elements study of elements become____________.

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

  1. difficult

  2. easy

  3. both A and B

  4. None of these

Show answer
Correct Option: B
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.

Classification of elements are done on the basis of ___________.

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

  1. atomic number

  2. atomic weight

  3. valency

  4. none of these

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Correct Option: A
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. 

The physical properties of elements changes according to_____________.

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

  1. classification of elements in groups and periods

  2. classification of elements in groups

  3. classification of elements in periods

  4. None of these

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Correct Option: A
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.

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

Show answer
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 $\text{A}$