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LEARNING GUIDE / 01

Reading the table,
one tile at a time.

The periodic table is more than a list of symbols. Its layout is a map of atomic structure, chemical behavior, and the relationships between elements.

IN THIS GUIDE

  1. 01What an element tile tells you
  2. 02Periods and electron shells
  3. 03Groups and element families
  4. 04Reading patterns

Start with an element tile

Every tile gives you a compact identity card for an element. Read it from the most fundamental number outward: the atomic number tells you which element it is, while the symbol and name make it easy to recognize.

8OOxygen

Atomic number: 8 means every oxygen atom has eight protons.
Symbol: O is the internationally used shorthand.
Name: Oxygen is the element’s full name.

The number at the bottom of a tile is usually the relative atomic mass. It is an average that accounts for the naturally occurring isotopes of an element, so it is often not a whole number.

Read across: periods

The seven horizontal rows are called periods. Elements in the same period have the same number of occupied electron shells. As you move from left to right, the atomic number increases by one and the outer electrons gradually fill.

PERIOD 1Only one electron shell: hydrogen and helium.
PERIOD 2Two shells: lithium through neon.
PERIOD 3Three shells: sodium through argon.
PERIOD 4+More shells, including the transition metals.

Across a period, elements generally become less metallic. The far-left elements tend to lose electrons, while those on the right tend to gain or share them. The noble gas at the end of each row is especially stable.

Read down: groups

The 18 vertical columns are groups. Elements in a group often behave alike because they have similar arrangements of electrons in their outermost shell.

Some useful families

  • Group 1 · Alkali metals: very reactive metals that readily lose one outer electron.
  • Group 2 · Alkaline earth metals: reactive metals that commonly lose two outer electrons.
  • Groups 3–12 · Transition metals: strong, conductive metals with varied chemistry.
  • Group 17 · Halogens: reactive nonmetals that commonly gain one electron.
  • Group 18 · Noble gases: gases with full outer shells and low reactivity.

Use color and position as clues

On Ozama’s table, color identifies broad families at a glance. The staircase boundary helps separate metals on the left from nonmetals on the right. Along the staircase are the metalloids, which have a mixture of metallic and nonmetallic properties.

These are useful tendencies, not absolute rules. Temperature, pressure, bonding, and the element’s specific chemical environment all matter. Treat the table as a starting map, then open an element’s profile for the details.

Quick check

Which element family is found in Group 18?

The noble gases—including helium, neon, and argon—are in Group 18.

← Return to the interactive table