Which of the following is a characteristic of lead?

The correct choice indicates that lead has an atomic number of 82. This characteristic is significant because the atomic number is a fundamental property that defines the element and determines its position on the periodic table. Each element has a unique atomic number corresponding to the number of protons in its nucleus, distinguishing it from other elements.

In the context of lead, which is a heavy metal, the atomic number plays a crucial role in understanding its chemical behavior and interactions. Lead is used in various applications, including batteries and radiation shielding, due to its density and atomic structure.

The other choices misrepresent properties of lead. For instance, claiming it is a gas at room temperature is inaccurate as lead is solid at room temperature. Describing it as non-toxic is misleading because lead is known to be toxic and can cause serious health issues. Lastly, it is not a noble gas, which refers to a specific group of elements (like helium or neon) that are characterized by their lack of chemical reactivity. Each of these mischaracterizations emphasizes the importance of the atomic structure and unique properties of lead as defined by its atomic number.