Question

The metal which is soft?
\[
  A.{\text{ }}Na \\
  B.{\text{ }}Pb \\
  C.{\text{ }}Al \\
  D.{\text{ }}Cu \\
 \]

Answer 1

Hint- In order to deal with this question first we will define the term soft metal then we will discuss the Mohs scale which is used to find the hardness of metals. On the basis of hardness of the metal we will find the soft metal amongst the given options.

Complete answer:
A metal which is easy to cut , dent for work without affecting malleable is called a soft metal.
The Mohs measurement of mineral hardness is a metric that characterizes scratch resistance to different minerals by the tendency to scratch softer material to higher.
So, according to this, sodium metal $\left( {Na} \right)$ is the softest metal among the given options followed by lead $\left( {Pb} \right)$, then aluminium $\left( {Al} \right)$ and copper $\left( {Cu} \right)$.
Hence, the softest metal amongst the given option is sodium or $\left( {Na} \right)$

Therefore, option A is the correct option.

Additional information-
Metals are lustrous. Sheets of metal thicker than a few micrometers appear invisible but green light is emitted by the gold leaf.
Broadly speaking, the forces holding the outer shell electrons of an individual atom are weaker than the attractive forces resulting from interactions between the atoms in the solid or liquid metal on the same electrons. The electrons involved become delocalised and a metal's atomic structure can be visualized effectively as a collection of atoms embedded in a cloud of relatively mobile electrons. That kind of contact is called a metal bond.

Note- Mineral hardness scale Mohs is named after the mineralogist Friedrich Mohs. The scale of Mohs is ordered by hardness and decides and minerals may scratch other minerals. The rocks contain one or more minerals. Talc is the softest compared to the scale: The other materials will scratch it. In some nuclear reactors sodium is used as a heat exchanger, and in the chemical industry as a reagent. Sodium salts also have more applications than the metal itself. Sodium chloride (common salt) is the most common sodium compound. It is added to food and used to de-ice roads in winter.