Notes

The transition metals are located in the center of the periodic table and include elements from groups 3 to 12. They often exhibit variable oxidation states and are known for their metallic properties.
The periodic table can be broadly divided into metals, nonmetals, and metalloids. Metals are typically on the left side, nonmetals on the right, and metalloids in between. Groups are often referred to by numbers and specific names. For example, Group 1 elements are called alkali metals, Group 17 elements are halogens, and Group 18 elements are noble gases. The periodic table is divided into groups (columns) and periods (rows). Elements in the same group share similar chemical properties, while those in the same period have similar electron configurations. The modern periodic table is arranged in order of increasing atomic number, which is the number of protons in an atom's nucleus. The modern periodic table is arranged in order of increasing atomic number, which is the number of protons in an atom's nucleus.Group 18 elements are known as noble gases. They are generally inert, meaning they have low reactivity. Helium, neon, argon, krypton, xenon, and radon are noble gases.