Answer:
Groups
Explanation:
1 A, 3 B, and 7 A are examples of group number on the periodic table
Group 1A are the alkali metals includes lithium sodium and potassium.
Group 3B in most periodic tables, lanthanum and actinium are considered to be a part of Group3B.
Group 7A are the halogens includes chlorine ,bromine and iodine.
They are all soft, silver metals. Due to their low ionization energy, these metals have low melting points and are highly reactive. The group 1A elements with their ns1 valence electron configurations are very active metals. They lose their valence electrons very readily.
All the Group 3B elements are rather soft, silvery-white metals, although their hardness increases with atomic number. They have higher ionization energies than the Group 1A and 2A elements, and are ionized to form a 3+ charges.
They have very high electronegativity. They have seven valence electrons . They are highly reactive, especially with alkali metals and alkaline earths metals.
Learn more about Group 1A,Group 3B and Group 7A,here:
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