1. Periods:
- Horizontal rows are called periods.
- There are 7 periods in the periodic table, numbered 1 through 7.
- Elements within a period have the same number of electron shells.
2. Groups (or Families):
- Vertical columns are called groups or families.
- There are 18 groups in the periodic table, numbered 1 through 18.
- Elements within a group have the same number of valence electrons (electrons in the outermost shell) and share similar chemical properties.
3. Blocks:
- The periodic table is also divided into four blocks based on the subshells that are being filled:
- s-block: Groups 1 and 2 (alkali and alkaline earth metals)
- p-block: Groups 13 to 18 (including nonmetals, halogens, and noble gases)
- d-block: Groups 3 to 12 (transition metals)
- f-block: Lanthanides and actinides (inner transition metals)
4. Other Classifications:
- Metals: Most elements are metals. They are generally shiny, malleable, ductile, and good conductors of heat and electricity.
- Nonmetals: Located on the right side of the periodic table, nonmetals lack the properties of metals.
- Metalloids: These elements have properties that lie between those of metals and nonmetals. They are also known as semimetals.
- Representative Elements: These elements are located in the s-block and p-block.
- Transition Elements: These elements are located in the d-block and have variable oxidation states.
Understanding these different sections helps you to understand the trends in properties across the periodic table.
