* Electrochemical Series: Lithium sits at the top of the electrochemical series, indicating it has a strong tendency to lose electrons and form positive ions. Copper, on the other hand, sits lower down, meaning it has a weaker tendency to lose electrons.

* Electronegativity: Lithium has a lower electronegativity than copper. This means lithium is more likely to give up electrons to form positive ions, making it more reactive.

* Ionization Energy: Lithium has a lower ionization energy than copper, meaning it requires less energy to remove an electron from a lithium atom. This makes lithium more prone to reacting and forming ions.

Evidence of Reactivity:

* Reaction with Water: Lithium reacts violently with water, producing hydrogen gas and lithium hydroxide. Copper does not react with water at room temperature.

* Reaction with Air: Lithium reacts readily with oxygen in the air, forming lithium oxide. Copper reacts with oxygen only at high temperatures, forming copper oxide.

Conclusion:

Due to its lower electronegativity, lower ionization energy, and higher position in the electrochemical series, lithium is significantly more reactive than copper.