Download our free Periodic Table app for mobile phones and tablets. Elements are arranged from left to right and top to bottom in the order of their increasing atomic numbers.

[170] Finally, hydrogen is sometimes placed separately from any group; this is based on its general properties being regarded as sufficiently different from those of the elements in any other group. The table here shows a widely used layout. Data for this section been provided by the British Geological Survey. If ever a Nobel Prize was awarded for sheer dogged hard work, then it was the one won by Richards in 1914. Giguère's Periodic helix (1965)[151] and Dufour's Periodic Tree (1996). Now next week, an element that can be manipulated to give us what we want. First ionisation energyThe minimum energy required to remove an electron from a neutral atom in its ground state. A uniform decrease in electron affinity only applies to group 1 atoms. [106][107] This so termed Law of Octaves was ridiculed by Newlands' contemporaries, and the Chemical Society refused to publish his work. [47] Previously, they were known by roman numerals. [185] A consistent set of electron configurations is then seen in group 3: scandium [Ar]3d14s2, yttrium [Kr]4d15s2 and lanthanum [Xe]5d16s2. [67], The electron affinity of an atom is the amount of energy released when an electron is added to a neutral atom to form a negative ion. The HTML