K (potassium) belongs to group IA of the periodic table, and has 1 valence electron. Br (bromine) belongs to VIIA, and has blank valence electrons. What is blank

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

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