Final answer:
Atoms of lead have identical chemical properties even though they may be isotopes with different masses. The density of a lead sample is consistent across different sample sizes because density is an intensive property.
Step-by-step explanation:
The properties of one atom of lead would generally be similar to those of another sample of lead because atoms of the same element have identical chemical properties, especially when considering a large chunk of an element which contains all naturally occurring isotopes. However, isotopes of lead may have different masses due to variations in the number of neutrons in the nucleus, although the chemical properties remain the same.
The concept of isotopes elaborates on this by acknowledging that while the atoms would have identical chemical properties, their physical properties, such as mass or nuclear stability, may differ. The realization of isotopes necessitated the modification of Dalton's atomic theory. For most practical purposes in chemistry, we deal with the averaged properties of all isotopes present in a sample, as this is usually how we observe the elements in nature.
In the case of lead or any other element, the density of the sample remains consistent, regardless of the sample size, as density is an intensive property.