Question

What is the molar mass of nobelium?

Answer 1

Hint : Periodic table consists of different elements. These elements have subatomic particles like electrons, protons and neutrons. The number of protons gives the atomic number. The sum of protons and neutrons gives the mass number which can also be called molar mass.

Complete Step By Step Answer:
Periodic table is the representation of chemical elements arranged in the increasing order of atomic numbers. These are divided into blocks namely s, p, d, and f blocks. The f-block consists of two series namely lanthanides and actinides.
Actinides are the chemical elements from the atomic numbers $90$ to $103$ . As the electron enters into $5f$ orbital these are also named as $5f$ series. Thorium is the first element belonging to $5f$ series and lawrencium is the last element that belongs to $5f$ series.
Nobelium is an element with atomic number $102$ and the number of protons in this element are $102$ and the number of neutrons is $157$ . Thus, the sum of the protons and neutrons gives the value of $259$ . Thus, the molar mass of nobelium id $259$ atomic mass units. The molar mass of elements can also be expressed in grams per mole.
The molar mass of nobelium is $259g{\left( {mol} \right)^{ - 1}}$ or $259$ amu.

Note :
In so many chemical elements the atomic number will not be half of the mass number. This is due to the difference in the number of neutrons and number of protons. Thus, the mass number will not always double to the atomic number. The atomic number of nobelium is $102$ but the mass number is not $204$ but it is $259$ .