Question

The electronic configuration of an element is 1s² 2s² 2p⁶ 3s² 3p³. What is the atomic number of the element, which is just below the above element in the periodic table?
(a) 33
(b) 34
(c) 36
(d) 49

Answer 1

The atomic number of the element which is just below the element having electronic configuration  1s² 2s² 2p⁶ 3s² 3p³ is 33.

What is an electronic configuration?

• Electronic configuration is defined as the distribution of electrons into the orbitals of an atom.
• With the help of Electron configurations we get information about the chemical nature of the elements.
• It also helps in classifying elements into different blocks like s-block, p-block, d and f block.

How to calculate atomic number?

The sum of the power of s, p, d and f in an electronic configuration gives the atomic number.

For example, The atomic number of the element having electronic configuration  $1s^{2} 2s^{2} 2p^{3}$ is 2+2+3 which is 7.

Answer 2

Element in the periodic table is an element with atomic number 33

Explanation:

• The concept of Mendeleev's periodic table and the modern periodic table is based on the study of electronic configuration.
• The electronic configuration of an element is 1s² 2s² 2p⁶ 3s² 3p³,4s²,3d¹⁰,4p³.    will have atomic number 2+2+6+2+3=15

• The Atomic number of the given element will be 15 +18 that is 33

• Atomic number of the element 33 is of Arsenic
• Element Arsenic could be placed in group 5 as per the modern periodic table.
• It has a total of 33 electron.