Answer:
Lithium has a lower density than lead.
The density of an element is determined by its atomic mass and the packing arrangement of its atoms. Lithium has an atomic mass of 6.94 atomic mass units (amu), while lead has an atomic mass of 207.2 amu, which is significantly higher.
In addition to atomic mass, the density of an element is also affected by the arrangement of its atoms. Lithium has a much larger atomic radius than lead, meaning that its atoms are less tightly packed together. This results in a lower overall density for lithium compared to lead.
To provide some context, the density of lithium is approximately 0.53 grams per cubic centimeter (g/cm3), while the density of lead is approximately 11.34 g/cm3. This means that lead is about 21 times denser than lithium.