In discussing halogen reactivity (as covered in Core Idea), it is a common practice to argue that as you go down the Group 17 elements it becomes harder for the elements to gain an electron to form a ...

On 17 February 1869, Russian chemist Dmitri Mendeleev jotted down the symbols for the chemical elements, putting them in order according to their atomic weights and inventing the periodic table.

Topics covered in the chemistry component include fundamental concepts related to atomic structure and the periodic table, chemical structural representations, functional groups, reactivity, toxicity, ...

1. Periodic Table as Arranged by Mendelejeff attention to the fact that “the eighth element, starting from a given one, is a kind of repetition of the first, like the eighth note of an octave in ...

The modern periodic table, arranged in rows and columns, was first introduced by Dmitri Mendeleev in 1869. At the time, it included the known elements and their properties, but Mendeleev predicted ...

How do we calculate mass and atomic numbers? VideoHow do we calculate mass and atomic numbers? This video is an interactive lesson in calculating an atom's mass and atomic number.

Institute of Inorganic Chemistry, University of Regensburg, Regensburg 93040, Germany ...

Most catalysts for bulk chemistry rely on elements from the transition metals groups, that block of elements that lives between the “towers” at either side of the periodic table. In addition ...

The 2024-25 Premier League table is tight from top to bottom as another season of chaos approaches its climax. [ MORE: Premier League 2024-25 schedule, how to watch live] There are so many big ...

Figure 1. The alkali metals are found in the left column on the periodic table. All are too reactive to be found in their elemental forms; the reactivity increases with atomic weight (lower in the ...

This table summarises some of the properties and uses of three halogens: ...