Question

Why does the boiling point of Group-1 metals decrease?

Answer 1

• The boiling point is the temperature at which a substance starts boiling and changes into a vapor state.
• Considering the metals of Group-1, as we move down the group, the atomic size increases as with every metal in the group, a new energy level is added up.
• The electrons present in the outermost shells are far from the nucleus. They are no longer under the influence of the nucleus.
• This weakens the force of attraction between the atoms of the metal.
• So, less energy is required for boiling to happen. The boiling will occur at a lower temperature.
• Hence, the boiling point of Group-1 elements decreases down the group.