Answer:
Multiply the element's atomic mass by the number of atoms of that element in the compound. This will give you the relative amount that each element contributes to the compound. For hydrogen chloride, HCl, the molar mass of each element is 1.007 grams per mole for hydrogen and 35.453 grams per mole for chlorine.
Since Alai is hitting each with a hammer, the physical property which he must be comparing on the two materials must be hardness. Solubility can be tested when you put them in a solvent. Odor can be tested with smell. Conductivity can be tested with electricity. Hardness can be tested with its resistance to the force that hits it.
Answer:
the number of neutrons in the nucleus
Explanation:
The mass number 205 is the total number of protons and neutrons in the nucleus. Lead has 82 protons, so a mass number of 205 indicates a nucleus with 123 neutrons.
Similarly, the mass number 208 indicates a lead nucleus with 126 neutrons.
The difference in atomic structure is the difference in the number of neutrons in the nucleus.