The Periodic Table of chemical elements represents
the material – “ingredients lists” of the present-day Universe.
- elements are arranged according to their atomic number – the same number of protons in the nucleus.
- in horizontal row – it’s called “periods and contain elements” that the same number of electron shells around the nucleus.
- in eight vertical columns – it’s called “group” that contain elements have similar chemical properties;
- group 0 – on the far right; this contains the inert noble gases. (diagram: Group 0)
- group 1 – contains the alkali metals; surprisingly – hydrogen is chemically an alkali metal. (diagram: Group 1)
- group 2 – contains the alkali earth metals. (diagram: Group 2)
- group 3 to 8 – contains poor metals and non-metals; with the halogens in group 7. (diagram: Group 3 to 8 / Group 7)
- metallic transition elements (which have incomplete inner electron shells) – located in the middle between group 2 and group 3. (diagram: Group 2 to 3)
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