Question

Which period is the longest period in the Modern Periodic Table?

Answer 1

Hint: The periodic table is a tabular arrangement of elements in groups and periods that illustrates regular trends in element properties. Mendeleev's periodic law and a periodic table were used to develop the modern periodic table.

Complete Step By Step Answer:
Periods are known as the horizontal rows of the periodic table. Each represents the consecutive occupation of orbitals in the atom's valence shell, with long periods corresponding to the occupation of orbitals in the d subshell.
The sixth period contains $32$ elements ( $Cs$ to $Rn$ ) and is also known as the longest period.
The first period contains only two elements H and He and is known as the shortest period.
The second period ( $Li$ to $Ne$ ) and the third period ( $Na$ to $Ar$ ) contain $8$ elements each and are known as short periods.
The fourth period ( $K$ to $Kr$ ) and the fifth period ( $Rb$ to $Xe$ ) contain $18$ elements each and are called long periods.
Hence, the sixth period is known as the longest period in the periodic table.

Additional Information:
The s-block, the p-block, the d-block, and the f-block are the four blocks that make up the current periodic table of elements. The types of orbitals that contain the element's valence electrons are used to classify it. For example, s-block elements have valence electrons in s-orbitals and d-block elements have their valence electrons in d-orbitals.

Note:
A row of chemical elements in the periodic chart is called a period. The number of electron shells in each element in a row is the same. Each successive element in a period has one more proton than its predecessor and is less metallic.