Question

The element californium belongs to a family of:
(A) Actinide Series.
(B) Alkali Metal Family.
(C) Alkaline Earth Family.
(D) Lanthanide Series.

Answer 1

Hint : We know that all the elements in the actinide series are heavy because of their large atomic mass. The elements belonging to this series have an atomic mass ranging from $227g/mol$ to $262g/mol$ . The atomic mass of hydrogen is one therefore; one can have a clear idea of comparatively how heavier these elements are.

Complete Step By Step Answer:
One of the most important properties of actinides is that they are radioactive in nature. The elements in this series are highly radioactive. Radioactive refers to breaking down of the nucleus into smaller particles. The smaller particles are Alpha particles, Beta particles as well as Gamma Particles. The elements in the Actinide series release a large amount of energy on radioactive decay.
The elements of Actinides are used as nuclear reactors and in nuclear weapons. There are different uses of Uranium and Thorium. Some of the elements in the actinides series are also used as smoke detectors. The Actinides are typical metals and they have properties of D block and F block elements. There are several oxocation of the elements in Actinides series whereas there is no oxocation in Lanthanides. The compounds that are formed by Actinides are very basic in nature as opposed to the compounds found by Lanthanides. The lanthanides and actinides are often called inner transition metals.
The element californium $\left( Cf \right)$ belongs to the family of actinide series. Its atomic number $\left( Z \right)$ is $98.$ It belongs to $7th$ period and the $3rd$ group.
Therefore, the correct answer is option A.

Note :
Remember that the actinides are Metals which are typical in nature. The actinides are soft, shiny, silver in color and have a good density and plasticity. Some of the actinides can also be cut with the help of a simple knife. Thorium has a similar hardness to soft steel and can be heated to roll into sheets or pull into a wire. The properties of elements in the actinide series are the same as D block. They can lose to multiple electrons and form a variety of ions.