49 total
The noble gases (Group VIII) represent one of the most remarkable discoveries in the history of the Periodic Table. When Mendeleev first constructed his table, he successfully predicted the existence and properties of some undiscovered elements. However, there was no indication that an entire group of elements remained to be discovered.
Analysis of air by John William Strutt (Lord Rayleigh) led to the discovery of argon in 1894. Because of their lack of reactivity, there was no clear sign of the existence of these gases.
There was no suitable place in the Periodic Table for an individual element with argon's properties. This pointed to the existence of an entirely new group.
Key discoveries:
All of the noble gases are present in the Earth's atmosphere. Together they make up about 1% of the total, though argon is the most common.
The noble gases are particularly unreactive. They were sometimes referred to as the inert gases, meaning they did not react at all. However, since the 1960s, some compounds of xenon and krypton have been made and their name was changed to the noble gases.
Key Term: Noble gases are the elements in Group VIII of the Periodic Table, characterized by their extreme unreactivity and stable electronic configurations.
The atoms of the noble gases do not combine with each other to form molecules or any other form of structure. They exist as single, isolated atoms (monatomic).
The noble gases have extremely low melting points and boiling points. This reflects the weak forces between their atoms.
Notable physical property:
Sign in to view full notes