Question

Which alkali metal does not exhibit photoelectric effect_______.

Answer 1

Alkali metals:

• Alkali metals constitute elements of Group-$1$.
• The elements that belong to alkali metals are discussed below:

1. Lithium $\left(\mathrm{Li}\right)$
2. Sodium $\left(\mathrm{Na}\right)$
3. Potassium $\left(\mathrm{K}\right)$
4. Rubidium $\left(\mathrm{Rb}\right)$
5. Cesium $\left(\mathrm{Cs}\right)$
6. Francium $\left(\mathrm{Fr}\right)$

• Alkali metals are very reactive in nature.

Photoelectric effect:

• The phenomenon of emission of electrons when electromagnetic radiation strikes the surface of metals is called the photoelectric effect.
• As alkali metals emit electrons when radiation strikes their surface thus they hold the property of exhibiting a photoelectric effect.
• The ability to exhibit the photoelectric effect is due to the weak value of the ionization energy of alkali metals
• Lithium metal does not emit photoelectrons due to the high value of ionization energy.