Question

Please help, I'm confused and it's due very soon!

1. Draw the atomic structure of an atom of lanthanum with an atomic mass of 139 amu. Calculate the correct number of protons, neutrons, and electrons. Show the structure of the electrons within their shells.

2. Why is this rare earth metal used to store hydrogen fuel in electric-powered vehicles?

3. How can the periodic table be used to predict the reactive nature of lanthanum?

Answer 1

1. Lanthanum-139 atom is the stable isotope of lanthanum with relative atomic mass 138.906348, 99.9 atom percent natural abundance and nuclear spin 7/2.

2. In fact, over 80% of electric cars sold globally utilized permanent magnet-based motors in 2019. These magnets are typically made with rare-earth materials such as neodymium and dysprosium, which have a very geographically constrained supply chain.

3. It is the second most reactive of the rare-earth metals after europium. Lanthanum oxidizes in air at room temperature to form La2O3. It slowly reacts with water and quickly dissolves in diluted acids, except hydrofluoric acid (HF) because of formation of a protective fluoride (LaF3) layer on the surface of the metal.

Step-by-step explanation: