Interactive periodic table

What this table shows

Every substance is made of elements, and the periodic table arranges all the known elements by atomic number, the number of protons in each atom. This version shows the first 20, from hydrogen (1) to calcium (20), which are the elements most students meet first. Metals and nonmetals are colored differently. In Explore, tapping an element shows its name, symbol, atomic number, group, period, whether it is a metal or a nonmetal, and one fact. Quiz me names an element and the student taps it.

• Periods are the rows. Elements in the same period have the same number of occupied electron shells.
• Groups are the columns. Elements in the same group have the same number of electrons in their outer shell, so they tend to react in similar ways.
• Group 1 (lithium, sodium, potassium) are the alkali metals, which react strongly with water. Hydrogen sits above them but is a nonmetal gas.
• Group 17 (fluorine, chlorine) are the halogens, which are very reactive nonmetals.
• Group 18 (helium, neon, argon) are the noble gases, which are very unreactive.

Common misconceptions

Students often think the table is arranged by atomic mass. Mendeleev's early tables were roughly ordered by mass, but the modern table is ordered by atomic number. A second mix-up is between elements and compounds: water and salt are not on the table because they are compounds, made of elements chemically joined together.

The line between metals and nonmetals is not perfectly sharp. Boron and silicon have some properties of each and are often called metalloids or semimetals. This table colors them with the nonmetals. Hydrogen is also unusual: it sits in group 1 because it has one outer electron, but it behaves very differently from the metals below it.

Where this fits in school

• England, Key Stage 3: pupils learn about the periodic table, periods and groups, metals and nonmetals, and the principles behind Mendeleev's table.
• England, GCSE (Years 10 and 11): students link the table to electron arrangement and study groups 1, 7 and 0 (also called group 18) in detail.
• US, grades 6 to 8: middle school physical science introduces elements, atoms and the layout of the table, building toward NGSS MS-PS1-1 on modeling atoms and molecules.
• US, high school chemistry: NGSS HS-PS1-1 asks students to use the periodic table as a model to predict the properties of elements from the pattern of outer electrons.

A 10-minute periodic table activity

• Ask the student to name any elements they already know and guess whether each is a metal or a nonmetal.
• In Explore, tap hydrogen, then follow the atomic numbers from 1 to 20. Ask what goes up by one each time (the number of protons).
• Tap down group 1 and then group 18. Ask how the two groups behave differently.
• Find where the metal color stops in each row. Ask which side of the table most metals are on.
• Finish with a Quiz me round.

Pair the table with the atom builder on this site. Building a sodium atom and then finding sodium on the table makes the link between protons, atomic number and position very concrete.

Learning more

Science is part of Eurekami's skill map, with lessons that draw science diagrams live and narrate them in English or Spanish. For older students, Exam Prep includes GCSE Combined Science practice papers.