Respuesta :

Edufirst

Answer:

  • The alkaline earth metals have 2  valence electrons.

Explanation:

Alkaline earth metals are the family of metals that belong to group (column) number 2 in the periodic table.

You can tell the number of valence electrons of the representative elements by the number of column: the ones digit is the number of valence electrons.

This is how this works:

Column number   ones digit     number of valence electrons

1                                  1                  1 (alkali metals)

2                                 2                 2 (alkaline earth metals)

13                                3                 3

14                                4                 4

15                                5                 5

16                                6                 6

17                                 7                 7 (halogens)

18                                 8                 8 (noble gases).

Of course, this is consequence of the electron configurations.

  • The electron configuration of the alkaline metals ends in ns², whrere n is the main energy level (principal quantum number), and the superscript 2 is the number of electrons in that level, so the number of valence electrons is 2.

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