Question

A major difference between the two rows of inner transition elements is that the lanthanides _____.

a.are radioactive and the actinides are not
b.occur in nature while most of the actinides are synthetic
c.are gases at room temperature and the actinides are solids
d.have no uses while the actinides have many

Answer 1

The key difference is that lanthanides mostly occur naturally while most actinides are synthetic and all actinides are radioactive; the lanthanides have various practical uses, whereas the actinides are noted for their use in applications that utilize their radioactivity.

Step-by-step explanation:

The major difference between the two rows of inner transition elements is that the lanthanides predominantly contain elements that occur naturally, whereas most of the actinides are synthetic. The lanthanides are a series of metallic elements from lanthanum (La) to lutetium (Lu), which have reactivity similar to group 2 elements. On the other hand, the actinides comprise elements from actinium (Ac) to lawrencium (Lr), all of which are radioactive elements. Only the first four actinides are found in nature, and the remaining actinides have been artificially created in the laboratory.

Both lanthanides and actinides are considered inner transition metals, named so because of their position in the two rows beneath the main body of the periodic table. While lanthanides have practical uses in optical devices, petroleum refining, and alloys, actinides are used in applications leveraging their radioactive properties, such as in powering cardiac pacemakers.

Answer 2

Due to the definition, the answer is: A major difference between the two rows of inner transition elements is that the lanthanides b.occur in nature while most of the actinides are synthetic.