Periodic Table Basics

Periodic Table Overview

• The periodic table is a tabular arrangement of elements, organized by their atomic number (number of protons in the nucleus), electron configuration, and recurring chemical properties.
• It is a powerful tool for chemists, physicists, and other scientists to classify and compare elements.

Periodic Table Structure

• The periodic table is divided into:
  • Horizontal rows: Periods (1-7)
  • Vertical columns: Groups (1-18)
  • Two main categories: Metals (left and center) and Nonmetals (right)
• Elements are arranged in order of increasing atomic number (Z) from left to right and top to bottom.

Periodic Trends

• Atomic radius: Decreases from left to right and increases from top to bottom
• Electronegativity: Increases from left to right and decreases from top to bottom
• Ionization energy: Increases from left to right and decreases from top to bottom
• Electronegativity and ionization energy are related to the element's position in the periodic table

Periodic Table Blocks

• s-block: First two columns (alkali metals and alkaline earth metals)
• p-block: Columns 13-18 (main group elements)
• d-block: Columns 3-12 (transition metals)
• f-block: Lanthanides and actinides (bottom-left corner)

Families of Elements

• Alkali metals (Group 1): Highly reactive, lose one electron to form a +1 ion
• Alkaline earth metals (Group 2): Less reactive, lose two electrons to form a +2 ion
• Halogens (Group 17): Highly reactive, gain one electron to form a -1 ion
• Noble gases (Group 18): Unreactive, full outer energy level

Metals, Nonmetals, and Metalloids

• Metals: Typically shiny, malleable, and good conductors of electricity
• Nonmetals: Typically dull, brittle, and poor conductors of electricity
• Metalloids: Intermediate properties, often semiconductors (e.g., silicon, germanium)