The question asks to identify the block of the periodic table to which Lanthanides and Actinides belong. This requires knowledge of the organization of the periodic table based on the filling of electron orbitals.
D) f-block. Lanthanides involve the filling of 4f orbitals, and Actinides involve the filling of 5f orbitals. Hence, they are collectively known as f-block elements.
The question asks for the common name of elements in Group 1 of the periodic table, excluding hydrogen. This requires knowledge of the periodic table's group names and the specific characteristics of Group 1 elements.
Correct Option: B) Alkali metals are the elements found in Group 1 of the periodic table, excluding hydrogen. They are highly reactive metals that form strong bases (alkalis) when reacted with water.
The question asks to identify the common name for Group 17 elements of the periodic table. This requires knowledge of the classification of elements in the periodic table based on their group numbers and characteristic properties.
Correct Option: C) Halogens — Group 17 elements, including Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), and Astatine (At), are collectively known as Halogens. The word "halogen" comes from Greek words meaning "salt-forming" because these elements readily react with metals to form a wide range of salts.
The question asks to identify the group of elements characterized by completely filled outer shells. This is a fundamental concept in chemistry related to the periodic table and electron configurations.
Correct Option: D) Noble gases are the Group 18 elements that have completely filled outer electron shells, making them very stable and unreactive.
The question asks for the common name given to the elements in Group 2 of the periodic table. This requires knowledge of the classification of elements based on their position in the periodic table.
Correct Option: B) Alkaline earth metals
The question asks to identify the scientist who arranged 63 known elements by increasing atomic weight and left gaps for undiscovered elements. This is a direct recall question about the history of the periodic table.
Dmitri Mendeleev is renowned for his work in 1869, where he published his periodic table. He arranged the then 63 known elements in order of increasing atomic weight. A crucial aspect of his work was leaving blank spaces in his table, predicting that these spaces would eventually be filled by elements yet to be discovered. He even predicted the properties of some of these undiscovered elements, such as eka-aluminium (gallium) and eka-silicon (germanium), which were later found to match his predictions remarkably well.
D) Dmitri Mendeleev — Mendeleev is credited with creating the first widely accepted version of the periodic table. He arranged the 63 known elements by increasing atomic weight and left gaps for undiscovered elements, predicting their properties accurately.