Why is gold heavier than lead?

In summary, lead nuclei have a higher mass and smaller atomic radius compared to gold nuclei. Despite this, lead is actually lighter than gold with a lower density. Both elements have a face-centered cubic crystal structure, indicating equal packing efficiency. The question of why lead is lighter than gold remains unanswered and can be further explored by researching the lattice constant and its relation to ionic radius. Though, it is important to note that the lattice constant and ionic radius are not equivalent.
  • #1
kiskrof
13
1
Not only are lead nuclei heavier than gold ones (207 vs 200), but the atoms are smaller (ionic radius 119pm vs 137pm). There is every reason for Pb to be heavier. Why is it lighter? (11.34 vs 19.31 g/cm^3)

They both have a FCC crystal structure, so the packing should be equally efficient.

Source: https://courses.edx.org/courses/course-v1:MITx+3.091x+3T2016/periodic_table/ (unfortunately, you probably need an edx account to visit)

Ignorance is lead, your answer will be gold to me. Thanks!
 
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  • #2
Your question would be better phrased by replacing the word "heavier" with the word "denser". Try googling.
 
  • #3
kiskrof said:
but the atoms are smaller

Not in a lattice they aren't. The lattice constant is not the ionic radius.
 

1. Why is gold heavier than lead?

Gold is heavier than lead because it has a higher density. Density is a measure of how much mass is packed into a given volume. Gold has a density of 19.3 grams per cubic centimeter, while lead has a density of 11.3 grams per cubic centimeter. This means that for the same volume, gold has more mass than lead, making it heavier.

2. What determines the density of an element?

The density of an element is determined by its atomic structure. Specifically, it is influenced by the mass and arrangement of the atoms that make up the element. The more tightly packed the atoms are, the higher the density will be.

3. Is the weight of an element the same as its density?

No, weight and density are two different measurements. Weight is a measurement of the force of gravity on an object, while density is a measure of how much mass is packed into a given volume. While gold may be heavier than lead, it does not necessarily mean it has a greater weight.

4. Can the density of an element change?

Yes, the density of an element can change under certain conditions. For example, if an element is heated and expands, its density will decrease since the same amount of mass is now spread out over a larger volume. Additionally, the density of an element can be affected by pressure, temperature, and other factors.

5. How does the density of gold and lead affect their uses?

The difference in density between gold and lead makes them suitable for different uses. Gold's high density makes it ideal for use in jewelry, electronics, and coins, where small amounts of material need to have a high value. Lead's lower density makes it useful for applications such as shielding against radiation, as it can absorb more radiation for a given thickness compared to other materials.

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