Test: Periodic Classification of Elements - SSC MTS / SSC GD MCQ

Dmitri Mendeleev is credited with the development of the periodic table. He arranged the elements in order of increasing atomic weight and noticed a pattern of recurring properties.

The term 'periodic' refers to the recurring trends in element properties. This pattern repeats each time the elements move one period down.

The modern periodic table contains seven periods, or horizontal rows of elements.

The question asks which element is at the centre of the periodic table. The given options are:

• A) Hydrogen
• B) Helium
• C) Iron
• D) Carbon

However, none of these elements are located at the centre of the periodic table. The periodic table is arranged in order of atomic number, and with 118 currently recognised elements, the central element would be around element 59.

Element 59 is Praseodymium (Pr), which is not listed among the provided options. Therefore, none of these options match the correct answer.

The original solution stating that Iron is at the centre of the periodic table is incorrect because Iron (Fe) has an atomic number of 26 and is located in the d-block but not near the centre.

The correct element near the centre would be closer to element 59, which is Praseodymium (Pr).

The Noble Gases are located in Group 0 (or Group 18 in some versions) of the periodic table.

In the periodic table, elements are arranged in horizontal rows called periods.

Each period represents a new principal energy level, with elements showing trends in:

• Atomic size
• Properties

As you move across a period, you can observe various trends that help in understanding the behaviour of elements.

The sixth period of the periodic table contains the most elements, with a total of 32 elements. This is because it includes both the d-block and f-block elements, such as the lanthanides, making it the longest period in terms of the number of elements.

The elements in the periodic table are arranged in order of increasing atomic number, which represents the number of protons in an atom's nucleus. This determines an element’s chemical properties and placement in the table.

While atomic weight and electron configuration are related to an element’s position, they do not solely determine the arrangement.
Therefore, Correct Answer - Option D

John Newlands proposed the law of octaves, which was an early attempt at classifying the elements.

Hydrogen does not fit into any group in Mendeleev’s periodic table due to its unique properties.

The halogens are located in Group 17 of the periodic table, which includes elements such as:

• Fluorine (F)
• Chlorine (Cl)
• Bromine (Br)
• Iodine (I)
• Astatine (At)

These elements are known for their:

• High reactivity
• Tendency to form salts when combined with metals

The modern periodic law is based on atomic number, which is the number of protons in an atom's nucleus.

The modern periodic table, as classified by IUPAC, has 18 main groups. However, when including the inner transition metals (f-block elements split into lanthanides and actinides), there are 32 groups in total.

Since none of the provided options correctly state 32 groups, the correct answer is not among the choices given.

Hydrogen has the atomic number 1, which means it is the first element in the periodic table.

Radon, a Noble Gas, is located at the bottom right corner of the periodic table.

The d-block of the periodic table is where the transition metals are located. Transition metals are characterised by having electrons in their d orbitals, which distinguishes them from other elements in the s, p, and f-blocks.

This configuration contributes to properties such as:

• Being good conductors of electricity
• Exhibiting a wide range of oxidation states

Glenn T. Seaborg is credited with the discovery of the lanthanides and actinides.

The maximum number of electrons that a shell can hold is given by the formula 2n², where n is the principal quantum number of the shell.

• For the third shell (n = 3), the calculation is:
• 2 × 3² = 18

Therefore, the third shell can accommodate a maximum of 18 electrons.

The atomic number of Argon, which indicates the number of protons in its nucleus, is 18.

Element 118 in the periodic table is named Oganesson.