Difference Between Radon and Radium

The key difference between radon and radium is that radon is a noble gas, whereas radium is a radioactive element.

Although the names radon and radium sound similar, they are completely different chemical elements. They occur in different physical states. However, both these elements are radioactive elements due to their large atomic number.

CONTENTS

1. Overview and Key Difference
2. What is Radon 
3. What is Radium
4. Side by Side Comparison – Radon vs Radium in Tabular Form
5. Summary

What is Radon?

Radon is a noble gas having the chemical symbol Rn and atomic number 86. It is a radioactive element due to its large atomic number that makes it unstable. It is a colourless, odourless, and tasteless noble gas. Naturally, this element occurs in the intermediate steps of radioactive decay of thorium and uranium. Radon is the intermediate decay product of radium. The atomic mass of the most common and stable isotope of radon is 222. However, the half-life of this stable isotope is about 3.8 days. Since its decay occurs quickly, radon is among the rarest chemical elements on Earth.

Radon is a p-block element in group 18 and period 6. It has a complete electronic structure according to the octet rule. It has minus values for melting point and boiling point, which makes it an essential gas at room temperature and pressure conditions. In addition, it has a face-centred cubic crystal structure. When considering its magnetic properties, it is non-magnetic because there are no unpaired electrons in radon atoms. Moreover, it is the densest noble gas, and it is an inert gas.

What is Radium?

Radium is a radioactive chemical element having the chemical symbol Ra and atomic number 88. It is categorized as an alkaline earth metal because it is in the group 2 of the periodic table. In its pure state, it appears in white colour. Upon exposure to the air, it readily reacts with nitrogen and forms black coloured radium nitride. The most stable isotope of radium is Ra-226. The half-life of this isotope is approximately 1600 years.

Radium is in group 2 and period 7 of the periodic table. It is an s-block element. It has completely filled atomic orbitals, but it does not have all the electrons to obey the octet rule. At standard temperature and pressure, this element can exist in the solid-state. It has a body-centred cubic crystal structure. Since there are no unpaired electrons, it is non-magnetic. Radium is the only radioactive member in group 2 of the periodic table. In its pure state, this chemical element has a volatile nature. It has very high melting and boiling points.

What is the Difference Between Radon and Radium?

The key difference between radon and radium is that radon is a noble gas, whereas radium is a radioactive element. However, both these elements are radioactive because they have large atomic numbers. Furthermore, Radon is the intermediate decay product of radium. In addition, the half-life of radon is about 3.8 days, while the half-life of radium is about 1600 years.

The following table summarizes the difference between radon and radium.

Summary – Radon vs Radium

Although the names radon and radium sound similar, they are completely different chemical elements. The key difference between radon and radium is that radon is a noble gas, whereas radium is a radioactive element. However, both these elements are radioactive because they have large atomic numbers.

Reference:

1. Hanusa, Timothy P. “Radium.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 14 Mar. 2019, Available here.
2. “Radium.” Wikipedia, Wikimedia Foundation, 24 Apr. 2020, Available here.
3. “Radon.” Wikipedia, Wikimedia Foundation, 20 May 2020, Available here.

Image Courtesy:

1. “86 radon (Rn) enhanced Bohr model” By Ahazard.sciencewriter – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Radium226” By grenadier – Own work (CC BY 3.0) via Commons Wikimedia