How did knowing the number of valence electrons in one of the alien elements to identify it? explain how the table was used to accomplish this task.

All elements in the same group of the periodic table have the same number of valence electrons. The number of valence electrons always matches the ones place digit of the group number. Knowing the valence electrons of an alien element allows matching it with its group

Explanation:

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"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."