Question:

The metal that produces red-violet colour in the non-luminous flame is

Updated On: Mar 4, 2024
  • $Ba$
  • $Ag$
  • $Rb$
  • $Pb$
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is C

Solution and Explanation

Alkali metals and their salts impart a characteristic colour to flame. The reason for flame colouration is that the energy of the flame causes an excitation of the outermost electrons which when return to their original position, give out the energy so absorbed in the visible region. Thus, Rb gives a red-violet colour to the flame.
Was this answer helpful?
0
0

Concepts Used:

Group 1 Elements

Group one of alkali metals is s-block elements with just one electron in their s-orbital. They are are alkali metals. They are named so because of the alkaline nature of the hydroxides and oxides.

Alkali metals are characterized by one s-electron in the valence shell of their atoms.

Alkali metals have a corresponding [Noble gas] ns1 electronic configuration. They occupy the first column of the periodic table. Alkali elements are:

  • Lithium(Li)
  • Sodium(Na)
  • Potassium (K)
  • Rubidium (Ru)
  • Cesium (Cs)
  • Francium (Fr)

They have occupied successive periods from first to seven. Francium is a radioactive element with very low half-life.

Electronic Configuration:

  • Alkali metals have one electron in their valence shell.
  • The electronic configuration is given by ns1. For example, the electronic configuration of lithium is given by 1ns1 2ns1.
  • They tend to lose the outer shell electron to form cations with charge +1 (monovalent ions).

This makes them the most electropositive elements and due to the same reason, they are not found in the pure state.