Respuesta :

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Explanation:

Groups are numbered 1–18 from left to right. The elements in group 1 are known as the alkali metals; those in group 2 are the alkaline earth metals; those in 15 are the pnictogens; those in 16 are the chalcogens; those in 17 are the halogens; and those in 18 are the noble gases.

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Answer:

The s-, p-, and d-block elements of the periodic table are arranged into 18 numbered columns, or groups.