Group 0: Noble Gases

Group 0, also known as noble gases, is a group of non-metal elements located on the far right column of the periodic table.

A periodic table displaying elements grouped by their type. The elements are presented in coloured blocks according to their category: nonmetals in pink, metals in green, and noble gases in turquoise. Each element is represented by its symbol and atomic number. For instance, 'H' with number '1' for Hydrogen is in the top-left corner, and 'Og' with number '118' for Oganesson is in the bottom-right. On the top, a colour legend indicates the association between each colour and the type of element.

  • Noble gases are known for being unreactive and stable due to having a complete set of electrons in their outermost shell.

Mendeleev did not include the noble gases in the original periodic table because, at the time, most elements were discovered through reactions with known elements. However, since noble gases are the least reactive elements, they remained undiscovered.

Therefore, the noble gases were not discovered until after he had developed the table.

The table below shows the electronic configurations of the first three noble gases:

Noble gasElectronic structure

Below is the structure of the atom of the first noble gas, which is helium.

A simplified atomic model of a Helium (He) atom. At the centre is a large pink sphere labelled 'He' representing the nucleus. Orbiting this nucleus is a circular path with two blue spheres, symbolising the two electrons of Helium.

The helium atom has two electrons in its first energy level, which can only hold a maximum of two electrons, making it full and stable. As a result, helium does not react chemically.

Below is the structure of Neon, which is the second noble gas.

A simplified atomic model of a Neon (Ne) atom. At the centre is a large orange sphere labelled 'Ne' representing the nucleus. Surrounding the nucleus are two concentric circular paths, each with multiple pink spheres. The inner circle has two pink spheres and the outer circle has eight, symbolising the electrons of Neon.

Neon, the second noble gas, has 10 electrons in total. Out of these 10 electrons, 8 are located in the second energy level, which can hold a maximum of 8 electrons. This means that the outer shell of neon is full, making it stable and unreactive, just like helium.

All group 0 elements have boiling points lower than room temperature, which makes sense as they are called noble “gases”. However, as you move down the group, the boiling points increase due to the increase in the relative atomic mass. Among them, helium has the lowest boiling point at -269 ºC, while radon has the highest, at -60 ºC.

A vertical bar graph titled "BOILING POINT (°C)" displaying the boiling points of various noble gases. The y-axis ranges from 0 to -300°C. The gases, from left to right, are Helium, Neon, Argon, Krypton, Xenon, and Radon. The bars show increasing boiling points from Helium to Radon, with Helium having the lowest near -270°C and Radon the highest just below -50°C. The bars are coloured in shades of green.

The reason for the increase in boiling point is related to atom size. Larger atoms have stronger intermolecular forces between them. This means that more energy is required to overcome these forces and convert the substance from a liquid to a gas.

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