Uranium is a radioactive element that exists in small amounts in nature, and its natural decay produces radium. This occurs naturally around the world and is harmless to humans at low concentrations, but when the concentration of radon increases, it can cause serious health problems.
This is the case because these particles get embedded in the lungs and stay there when people inhale them. They will continue to decay over time, and this radioactive decay can cause serious health problems for humans, especially lung cancer.
Key Takeaways
- Radon is a radioactive gas found in soil, rock, and water and can cause lung cancer.
- Radium is a highly radioactive element found in the soil and rock and can cause bone cancer.
- The primary difference between radon and radium is that radon is a gas, while radium is solid.
Radon vs Radium
Radon is an inert gas with the atomic number 86, and its chemical symbol is Rn. It is a P-block element and it is very rare to come across. Radium is a solid element with the atomic number 88 on the periodic table. Also, it is a rare S-block element, and its chemical symbol is Ra.

Radon is a radioactive gas that is produced when radium decays. It is a member of the uranium decay series, in which uranium decays into a number of different elements until it reaches the stable element lead.
Radon decomposes into polonium and alpha particles when it decays. It features a face-centred cubic crystal structure as well. When radon is ingested, it decays into polonium, another radioactive element, potentially increasing the bodyโs radioactive load.
This can lead to the development of malignant cells.
Radium is a metal that forms as a result of the breakdown of uranium and lead. Itโs well-recognized that itโs a highly radioactive substance.
It was found in a uranium ore by Pierre and Marie Curie in 1898. The element was identified because it has the ability to shine.
Marie Curie and a colleague created the metal in its pure form for the first time in 1911. The elementโs name originates from the Latin word โray,โ which refers to its radioactivity.
Comparison Table
Parameters of Comparisonย | Radon | Radium |
---|---|---|
Definitionย | Radon is a noble gas with the chemical symbol Rn. | Radium is a radioactive element with the chemical symbol Ra. |
Block Element | p- block | ย s-block |
State of matter | Gas | Solid |
Atomic Number | 86 | 88 |
Existence | Very Rare | Less Rare than Radon |
What is Radon?
Radon is a noble gas with the atomic number 86 and the chemical symbol Rn. It is a radioactive element because of its high atomic number, which causes it to be unstable.
Itโs a noble gas thatโs colourless, odourless, and tasteless. This element naturally occurs in the intermediate stages of thorium and radioactive uranium decay.
The intermediate decay product of radium is radon.
The most common and stable isotope of radon has an atomic mass of 222. On the other hand, this stable isotope has a half-life of around 3.8 days.
Radon is one of the rarest chemical elements on the planet due to its rapid disintegration. Radon is a p-zone element with a period of 6 and a group of 18.
According to the octet rule, it has a complete electronic structure. Its melting point and boiling point are both negative, making it an important gas at ambient temperature and pressure.
There are no unpaired electrons in radon atoms. Therefore it is nonmagnetic.
It is also the densest noble gas and an inert gas. Because of the mutagenic properties of the radioactive gas, it has been hypothesized that it may have played a crucial role in evolution.
More mutations in the local plant, animal, and microbial life may occur in areas with higher radon concentrations in rural rocks, leading to more mutations and, thus, more evolution among these groups.

What is Radium?
Radium is a radioactive chemical element with the atomic number 88 and the chemical symbol Ra. Because it belongs to group 2 of the periodic table, it is classified as an alkaline earth metal.
It has a white colour in its purest form. When exposed to air, it rapidly combines with nitrogen to create radium nitride, which is black in colour.
Ra-226 is the most stable isotope of radium. This isotope has a half-life of about 1600 years.
Radium belongs to the periodic tableโs group 2 and period 7. Itโs an s-block component.
It contains fully filled atomic orbitals, but not all of the electrons are required to follow the octet rule.
This element can exist in solid form at normal temperatures and pressures. It features a cubic crystal structure that is centred on the body.
It is non-magnetic because there are no unpaired electrons. Radium is the sole radioactive element in Periodic Table Group 2.
This chemical element is volatile in its natural state. Its melting point and boiling point are both high.
The radioactivity of the element radium is shown by the fact that Marie Curieโs radium-studying notebooks are still too radioactive to be handled safely. Therefore, radium easily increases the risk of blood diseases such as cancer and anaemia, vision problems such as cataracts, and dental problems.
Miners, particularly uranium miners, are likely to be exposed to higher levels of radium. Radium levels are also greater in well water and the air around fossil fuel companies.
Humans and other life forms are continually exposed to non-harmful quantities of radium radiation due to the elementโs abundance in the Earthโs crust.
Main Differences Between Radon and Radium
- Radon is a noble gas with the chemical symbol Rn whereas Radium is a radioactive element with the chemical symbol Ra.
- At room temperature, radon is a solid, whereas radium is a gas.
- Radon is the element of the p-block, whereas Radium is the element of the s-block.
- Radium has an atomic number of 88, while radon has an atomic number of 86.
- Radon is very rare, whereas Radium is less rare than Radon.

- https://aslopubs.onlinelibrary.wiley.com/doi/abs/10.1002/lno.11678
- https://www.sciencedirect.com/science/article/pii/S027277140700306X
Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.