Chapter 2, Problem 2.71E

Calculating Atomic Mass Magnesium has three naturally occurring isotopes with masses 23.99,24.99,and25.98amu and natural abundances 78.99,10.00,and11.01%. Calculate the atomic mass of magnesium.

Average atomic masses listed by JUPAC are based on a study of experimental results. Bromine has two isotopes 79Br and 81Br, whose masses (78.9 183 and 80.9 163 amu) and abundances (50.69% and 49.3 1%) were determined in earlier experiments. Calculate the average atomic mass of bromine based on these experiments.

Who discovered the nucleus? Describe the experiment that led to this discovery.

A fundamental idea of Daltons atomic theory is that atoms of an element can be neither created nor destroyed. We now know that this is not always true. Specifically, it is not true for uranium and lead atoms as they appear in nature. Are the numbers of these atoms increasing or decreasing? Explain.

The CRC Handbook, a large reference book of chemical and physical data, lists two isotopes of rubidium (Z=37). The atomic mass of 72.15 of rubidium atoms is 84.9118u. Through a typographical oversight, the atomic mass of the second isotope is not printed. Calculate that atomic mass.

Naturally occurring sodium has a single isotope. Determine the following for the naturally occurring atoms of sodium: a. The number of neutrons in the nucleus. b. The mass in u of the nucleus to three significant figures.

Naturally occurring aluminum has a single isotope. Determine the following for the naturally occurring atoms of aluminum: a. The number of neutrons in the nucleus. b. The mass in u of the nucleus to three significant figures.

What particles are found in the nucleus of an atom? What is the charge of the nucleus?

How many platinum atoms are in a pure platinum ring weighing 4.32 g?