The major groups on the periodic table include Alkali Metals, Alkaline Earth Metals, Transition Metals, Halogens, and Noble Gases. Which term describes these categories?

• A. Periods
• B. Blocks
• C. Subshells
• D. Groups (Families)

Answer: (D)

These categories describe groups (or families). The periodic table is arranged in columns called groups, where elements in the same group share similar chemical properties because they have the same number of valence electrons in their outermost shell. For example, alkali metals all have one valence electron, halogens have seven, and noble gases have a full valence shell, giving them similar reactivity. Transition metals belong to the d-block, reflecting their characteristic electron configurations, but they’re still organized as a group of elements with related chemistry.

The other terms don’t fit as descriptions of these categories. Periods are the horizontal rows, not the families. Blocks refer to broad regions based on the orbital type in which the last electron enters (s-block, p-block, d-block, f-block). Subshells are about the types of orbitals (s, p, d, f) within atoms, not how the elements are categorized into groups on the table.