Chemistry

Periodic Classification and Elements

1,176 Questions

Periodic classification organizes chemical elements based on atomic structure, periodic laws, and elemental properties. It covers historical classification systems, electron configurations, and periodic trends. Test takers preparing for chemistry sections will find these questions crucial for mastering fundamental element properties and atomic interactions.

Periodic table structureAtomic orbitalsElement identificationPeriodic laws

Periodic Classification and Elements Questions

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

Hydrogen differs from elements of VII-A group as:

  1. it can gain one electron

  2. it has one electron in its valence shell

  3. its electronic configuration is different from other elements
  4. both $B$ and $C$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hydrogen differs from elements of $VII-A$ group as:


(A) Hydrogen can either share or gain or lose one electron whereas the elements of $VII-A$ group can gain one electron.

(B) Hydrogen has one electron in its valence shell whereas elements of $VII-A$ group have 7 valence electrons.

(C) The electronic configuration of hydrogen is different from the elements of $VII-A$ group.

So, options B and C are the correct answers. 

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

Hydrogen resembles IV-A elements in what respect?

  1. All are metals.

  2. All are non metals.

  3. All are metalloid.

  4. They have half-filled electronic configuration.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

IV A group has half filled valence shell like carbon or silicon and it shares it with the hydrogen singly filled s orbital. They resemble have comparable I.P. and E.A.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

____________ element has one electron in its outermost shell and attains duplet configuration after one more electron and attains stability.

  1. Hydrogen

  2. Fluorine

  3. Helium

  4. Berrylium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrogen has one electron in its outermost shell and attains duplet configuration after one more electron and attains stability.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

Hydrogen occupies a unique position in Modern Periodic Table.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hydrogen has electron configuration of $ 1s^{1}$.To become stable it can either accept to get helium configuration that is a stable configuration or it can even donate one electron. Hence it is very confusing where to place either in the metals group as it donates or in nonmetal group as it accepts an electron. Hence it occupies a unique position in the periodic table.

Multiple choice chemistry study of the first element - hydrogen position of hydrogen in the periodic table hydrogen in periodic table trends in groups and periods

The present position of hydrogen in the modern periodic table completely justifiable.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrogen has an electronic configuration of $1s^1$. So, it can accept one electron to complete its' outermost orbital which resembles to group $17$ of the periodic table. 

Also, it has only one electron in the outermost orbit which is shown by the elements in group 1. Therefore, the present position of hydrogen in the modern periodic table is not completely justified.
So the answer is False.

Multiple choice chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

Some elements show the property of existing in two or more distinct physical form which show different physical properties but same chemical properties. These distinct forms of an element are called :

  1. isomers

  2. allotropes

  3. compounds

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

Allotropes of carbon have a different physical form but chemically they are similar, e.g., diamond and graphite are allotropes of carbon which are chemically carbon compounds but physically diamond is the hardest material known while graphite is soft material.


Hence, option $B$ is correct,

Multiple choice chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

Some elements show the property of existing in two or more distinct physical form which shows different physical properties but same chemical properties. These distinct forms of an element are called:

  1. isomers

  2. allotropes

  3. compounds

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

The term allotrope refers to one or more forms of a chemical element that occur in the physical state. Graphite and diamond are both allotropes of carbon that occur in the solid state. Allotropism only refers to different forms of chemical elements.

Multiple choice chemistry the world of carbon organic compounds allotropes of carbon versatile nature of carbon

The number of free electrons in the outermost shell of carbon in graphite is:

  1. four

  2. one

  3. two

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

The number of free electrons in the outermost shell of carbon in graphite is one. Each $\displaystyle C$ atom is $\displaystyle sp^2$ hybridised. Each $\displaystyle C$ atom forms 3 covalent bonds with 3 other $\displaystyle C$ atoms. Thus, each $\displaystyle C$ atom has one electron in unhybridized $\displaystyle 2p$ orbital which it uses for $\displaystyle \pi $ bonding.

Multiple choice chemistry p- block elements-ii anomalous properties of nitrogen nitrogen - 15 group group 15 elements

An element X combines with hydrogen to form a compound $XH _3$. The element X is placed on the right side ofthe periodic table. What is true about the element X?
A. Has 3 valence electrons.
B. Is a metal and is solid.
C. Is a non-metal and is a gas.
D. Has 5 valence electrons.
E. $XH _3$  reacts with water to form a basic compound?

  1. A, B and C

  2. B,C and D

  3. C, D and E

  4. E, A and B
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Here, $X$ is nitrogen with atomic number 7 and electronic configuration $ { 1s }^{ 2 }{ 2s }^{ 2 }{ 2p }^{ 3 } $ 

It is a non metal belonging to group 15.
Solution of ammonia In water is alkaline in nature and is highly soluble in water.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

The close resemblance between the properties of an element of 2nd period with those of the element of 3rd period belonging to the next group is called:

  1. periodicity

  2. periodic trend

  3. diagonal relationship

  4. group trend
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Option $(C)$ is correct.

The close resemblance between the properties of an element of 2nd period with those of the element of 3rd period belonging to the next group is called diagonal relationship.
These pairs (lithium and magnesium, beryllium and aluminium, boron and silicon etc.) exhibit similar properties.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

Diagonal relationship is due to:

  1. identical ionization potential

  2. identical electron negativity

  3. identical sizes of ions

  4. same valence shell configuration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Option $(C)$ is correct.

The diagonal relationship is due to identical sizes of ions.
On moving rightward a period of the periodic table, the size of the atoms decreases, and on moving down a group the size of the atoms increases. Similarly, on moving rightward a period, the elements become more electronegative, whereas on moving down the group the element becomes more positive. These two factors work in opposite direction. Hence the elements that are present diagonally to each other have similar properties like atomic size, electronegativity, density, chemical properties of compounds.

Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

The first element of the groups 1 and 2 are different from other members of the respective groups. Their behaviour is more similar to the second element of the following groups. What is this relationship known as?

  1. Anomalous relationship

  2. Periodic relationship

  3. Diagonal relationship

  4. Chemical relationship
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The similarities (in many of properties) between first element of a group and second element of the next group is called diagonal relationship.
Thus, Li ( first element of group 1) shows diagonal relationship with Mg (second element of group 2).
Also, Be ( first element of group 2) shows diagonal relationship with Al (second element of group 13).
Also, B ( first element of group 13) shows diagonal relationship with Si (second element of group 14).
Multiple choice chemistry the s-block elements (alkali and alkaline earth metals) anomalous properties of lithium group 1 elements: alkali metals properties of s block elements

Diagonal relationship of elements in due to same:

  1. size

  2. mass number

  3. atomic number

  4. electron affinity
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
In addition to horizontal and vertical trends, there is a diagonal relationship between elements such as Li and Mg, Be and Al, B, and Si, that have an adjacent upper left/lower right relative location in the periodic table. 
These pairs of elements have similar size and electronegativity, resulting in similar properties. 

Diagonal relationships occur because of the directions in the trends of various properties as you move across or down the periodic table. Many of the chemical properties of an element are related to the size of the atom. Hence it is because of the same size.