Modern Periodic Table

Start with the Element Address

The modern periodic table is easiest to read as a seating chart. Each box is one element. The number that sets the seat order is called the atomic number, written as $Z$ , which is the number of protons in the atom's nucleus.

So, elements are not arranged by name or by the size of their symbols. They are arranged mainly by increasing $Z$ . Because the number of protons identifies the element, this order makes repeating chemical patterns visible.

Modern Periodic Table Pattern Model

Choose the part you want to read. Raised blocks show the main patterns: columns, rows, the middle region, lower series, metalloids, and noble gases.

MetalTransition metalMetalloidNonmetalNoble gasInner transition

Focus: A column with a similar outer pattern
Group: $1-18$
Period: $1-7$
Atomic number: $Z$

Atomic Structure

Modern Periodic Table

Start with the Element Address

Modern Periodic Table Pattern Model

Choose the part you want to read. Raised blocks show the main patterns: columns, rows, the middle region, lower series, metalloids, and noble gases.

MetalTransition metalMetalloidNonmetalNoble gasInner transition

Focus: A column with a similar outer pattern
Group: $1-18$
Period: $1-7$
Atomic number: $Z$

Region	How to read it
Metals	Many are on the left and in the middle of the table. Many metals conduct electricity and tend to lose electrons when forming ions.
Nonmetals	Many are in the upper-right part of the table. Many nonmetals tend to gain or share electrons when bonding.
Metalloids	They sit at the boundary between metals and nonmetals. Their properties are in between, for example silicon can be used as a semiconductor.
Noble gases	They are in group $18$ . These elements are very unreactive because their outer electron arrangement is stable.

Question	Self-check
What group do $\mathrm{Mg}$ , $\mathrm{Ca}$ , and $\mathrm{Sr}$ share?	All three are in group $2$ .
Why are $\mathrm{Na}$ through $\mathrm{Ar}$ in period $3$ ?	In the simple shell model, their outer main shell is the $\mathrm{M}$ shell.
Why are $\mathrm{B}$ , $\mathrm{Si}$ , and $\mathrm{Ge}$ often discussed as metalloids?	They sit in the transition area between metals and nonmetals.
Why do main-group elements in one group often have similar chemical properties?	Their valence electrons are the same or follow a similar pattern, so their reactions are often similar too.

Modern Periodic Table

Start with the Element Address

Modern Periodic Table

Start with the Element Address

Two Directions to Read Fluently

Color Is a Clue, Not a Memorization Target

Why Two Rows Sit Below

Check Patterns in the Periodic Table