Chapter 12, Problem 127E

Interpretation Introduction

Interpretation:Atomic number and electronic configuration of alkali metal next to francium should be determined.

Concept introduction:Alkali metals are those that belong to group 1 A. The atomic number in series of elements present is calculated by addition of numbers in regular manner. The numbers are 2, 8, 8, 18, 18, 32, and 32.

The process by which electrons are distributed in molecular or atomic orbitals is termed as electronic configuration and is arranged in accordance to Aufbau principle. Hund’s rule of multiplicity states that electrons are filled singly in an orbital initially and then pairing occurs with different spin. Thus atomic orbital is filled in accordance to this rule.

The electrons that are present in the outermost shell of an atom are termed as valence electrons. In accordance to Aufbau principle electrons are filled in lower energy level and then to higher level. The electrons are arranged in order from higher energy level to lower level is as follows:

  $s>p>d>f$

Electrons in orbitals are arranged as follows:

  $1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{2}3d^{10}4p^{6}4d^{10}5s^2$