When considering the number of valence electrons, we can observe the following patterns among metals, non-metals, and noble gases:
Metals: Metals tend to have fewer valence electrons, typically 1, 2, or 3. These metals are found on the left side and the middle of the periodic table. They readily lose electrons to achieve a stable electron configuration and form positive ions (cations).
Non-metals: Non-metals generally have a higher number of valence electrons, often 4, 5, 6, 7, or 8. Non-metals are found on the right side of the periodic table, including elements in the carbon, nitrogen, oxygen, and halogen groups. They tend to gain or share electrons to achieve a stable electron configuration and form negative ions (anions) or covalent bonds.
Noble gases: Noble gases, such as helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn), have full valence electron shells with 2 or 8 electrons (except for helium, which has only 2 electrons in total). This makes them chemically stable and less likely to form chemical bonds with other elements. Noble gases are located in Group 18 (VIII A) of the periodic table.
In summary, metals tend to have fewer valence electrons and readily lose them, non-metals generally have more valence electrons and tend to gain or share them, while noble gases have full valence electron shells and exhibit low reactivity due to their stable configurations.