Question

Which of the following is correct regarding the chemical symbol Ar.
${\text{A}}{\text{.}}$ One mole of argon
${\text{B}}{\text{.}}$ One atom of argon
${\text{C}}{\text{.}}$ Both a mole or an atom of argon
${\text{D}}{\text{.}}$ Neither a mole or an atom of argon
${\text{E}}{\text{.}}$ One molecule of argon

Answer 1

Hint: Here, we will simply proceed by defining the chemical element argon having chemical symbol Ar. Then, we will write down its existence in nature as monatomic or polyatomic.

Complete step-by-step answer:
Argon is a chemical element that includes the symbol Ar and atomic number 18. It is in the periodic table in group 18, and is referred to as a noble gas. Argon is the third most abundant gas available in the atmosphere on earth.
Argon is industrially produced through the fractional distillation of liquid air. Argon is often used as an inert shielding gas in welding and other high temperature industrial processes where unreactive compounds change into reactive ones. For example, graphite electric furnaces use an argon atmosphere to prevent graphite from burning. Argon is also used in incandescent, fluorescent, and other gas discharge tube applications. Argon produces a characteristic blue green gas laser. Argon is often used in starters with fluorescent glows.
Argon as solid, liquid, or gas is colourless, odourless, non-flammable, and non-toxic. Under most conditions, argon is chemically inert and forms no confirmed stable compounds at room temperature.
Monatomic is a mixture of the terms mono and atomic and refers to a single atom. It is usually applied to gases. A monatomic gas is one that does not bind atoms to each other. Examples at normal conditions include the noble gases like argon, krypton, and xenon, but at extremely high temperatures all chemical elements would be monotonous in the gas phase. Compared to polyatomic gases, the thermodynamic behaviour of a monatomic gas is extremely simple, since it is free of any rotational or vibrational energy.
Therefore, the chemical symbol Ar represents both a mole or an atom of argon and it is not represented as one molecule of argon since it exists as monatomic gas instead of appearing as a molecule due to the chemical inertness of argon.
Hence, option C is correct.

Note- An inert gas is a gas not undergoing chemical reactions under a given set of conditions. The noble gasses often do not react with many substances and have been historically called inert gasses. Generally, inert gases are used to prevent unwanted chemical reactions which degrade a sample.