Question

If the atomic number of an element is 33, it will be placed in the periodic table in the

• A. first group
• B. third group
• C. fifteen group
• D. seventh group

Answer 1

The Correct Option is C

To determine the placement of an element with atomic number 33 in the periodic table, we need to understand the structure and classification method of the periodic table. The modern periodic table is organized based on the increasing atomic number of elements, and elements are placed into specific groups or columns based on their electronic configurations.

1. The element with atomic number 33 is Arsenic (As), as we can find from the periodic table.
2. Arsenic has the electronic configuration: [Ar] \, 3d^{10} \, 4s^{2} \, 4p^{3}.
3. In this configuration, the outermost shell has 5 electrons (2 from the 4s orbitals and 3 from 4p orbitals), which characterize it as part of the p-block of the periodic table.
4. Arsenic falls under the group where elements have similar outer shell electron configurations. Here it matches the pattern of having 5 electrons in its outer shell, typical of the Group 15 (formerly known as Group V-A) elements, which include nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi).

Therefore, the element with atomic number 33, Arsenic, is situated in the fifteenth group of the periodic table. This aligns with the provided correct answer:

• Answer: Fifteenth Group

Explaining why the other options are incorrect:

• First Group: This group contains elements with a single electron in their outermost shell, such as alkali metals like lithium (Li), sodium (Na), etc.
• Third Group: This group begins the transition elements, characterized by having partially filled d-subshells.
• Seventh Group: Traditionally known as Group XVII or Group 17, consists of the halogens like fluorine (F), chlorine (Cl), etc., with seven electrons in their outermost shell.