Aufbauprinzip‘ – a German noun, meaning ‘Construction principle’.

By the AUFBAU principle, electrons will fill up orbitals in an element in order of increasing energy. Elements are placed in blocks on the Periodic Table, based on the last orbital which takes electrons in its electronic configuration (s, p, d or f).

Presently, the last element that has been named by IUPAC is Oganesson (118Og). Its last electron is in the 7p orbital hence, it is in the 7th period and p-block of the periodic table.

Period 7 in the Periodic Table

The seventh period ends with the element Oganesson. It contains 32 elements including actinides valence electrons in the 7s, 5f, 6d and 7p orbitals

The orbital next in energy to the 7p orbital is the 8s orbital and after that, we have the 5g orbital. Elements 119 and 120 will have their last electrons in the 8s orbital; they will be in the 8th period and s-block and then, what next? Where will elements 121 and subsequent elements be placed on the Periodic Table?

Where will elements 121 and subsequent elements be placed on the Periodic Table?

A new block

A new block will need to be created on the Periodic Table- the g-block. This will bring a major change to the appearance of the Periodic Table. The g-block will have eighteen (18) elements on each row.. its location and name will need to be published.

Will that be when all 18 elements on its first row are discovered or from the moment the first element on the block is discovered?


Mrs Chinyere Ogbodo,  a Nigerian Chemist, who enjoys discussing the Periodic Table of elements. She is the topper of Sciteum’s #elequiz. She is so passionate and participate actively in discussions on elements.

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