Question

Which of the following belongs to the representative group of elements in the periodic table?
A. Lanthanum
B. Argon
C. Chromium
D. Aluminium

Answer 1

It's important to remember that representative elements are defined by their electrical configuration, and they don't have variable valences. Internal orbits of representative elements are totally filled. Remember that the main group is made up of the elements helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, and fluorine, which are ordered in the periodic table as the lightest members.

Complete answer:
Representative elements are found in the first two families (Groups $\;I$ and $II$ on the far left) and the last six families or groups (on the right) of the Periodic Table.
Representative elements include elements such as $s -$ block and $p -$ block.
The $s -$ block elements with $1{s^2}$ and $2{s^2}$ outermost configuration are known as elements in groups $1$ and $2$ .
The $p -$ block elements belong to group $13 - 17$ , and their outermost configuration varies from $n{s^2}n{p^1}$ to $n{s^2}n{p^5}$ .
Aluminium belongs to the $p -$ block of the periodic table.
Argon is a chemical element in the periodic table's eighteen group. It is the third most abundant gas in the earth's atmosphere and is a noble gas.
Chromium is a strong, shiny metal with a silvery grey colour. It has a high melting point.it belongs to the $d -$ block.
Lanthanum is an $f -$ block element because its $f -$ orbitals are partially filled. Because lanthanum is their first element, the entire group is termed lanthanides, and they all have comparable properties.
Hence the correct option is D. Aluminium.

Note:
We must understand that the periodic table contains a wealth of information about each element and how they interact. To comprehend this, we must have a complete understanding of the electrical arrangements of these elements, as well as their physical and chemical properties.