Question

The total number of groups in the Modern Periodic Table is_______.
A.7
B.17
C.18
D.8

Answer 1

Hint: The periodic table is defined as a tabular array of the chemical elements organized by atomic numbers, from the element starting with the lowest atomic number, hydrogen, to the element with the highest atomic number, oganesson.

Complete Solution :
A periodic table consists of seven horizontal rows and 18 vertical groups. The atomic number of an element is defined as the number of protons present in the nucleus of an atom of that element.

ELECTRONIC CONFIGURATION OF ELEMENTS AND THE PERIODIC TABLE:
- We know that an electron in an atom is characterised by a set of four quantum numbers (n, I, m and s) where the principal quantum number (n) defines the main energy level known as the shell. We have also studied about the filling of electrons into different subshells (s, p, d and f) in an atom. This distribution of electrons into various subshells of an atom is called its electronic configuration. The location of any element in the periodic table is reflected by the quantum numbers of the last filled orbital. Here we will discuss the direct relation between the electronic configuration of the element and its location in the periodic table.
So, the correct answer is “Option C”.

Note: The indication of the period is given by the value of n for the outermost or valence shell. In other words, a successive period in the periodic table is associated with the filling of the next higher principal energy level like n = 1, n = 2, n = 3..... refers to the filling of the 1st, 2nd, 3rd and higher principal energy levels.