"Periodic table pdf" is typed by students in Class 9 to Class 12, in Year 9 to A-level, and by parents printing one for the wall, and most of what comes back is either a low-resolution image or a chart behind a sign-up. This page has a clean one: A4 landscape, 118 elements coloured by family, the number, symbol, name and mass in every cell, and a second page with the three rules that make the table readable and the short history of who built it. Then, because the table means different things at different levels, what your class actually needs from it.
The chart
Download the periodic table (PDF, A4 landscape, 2 pages). Print at 100 per cent; the cells are sized for an A4 sheet on a wall or inside a folder. The companion list of all 118 elements with symbols, names and masses is the same data as a table, for the students who need to look things up rather than see the shape.
Each cell carries four things: the atomic number top-left, the symbol large, the name, and the standard atomic weight rounded to two or three decimals. Where an element has no stable isotope the mass is the mass number of its most stable isotope in brackets, which is the convention exam boards use.
The three rules for reading it
Students memorise the table; chemists read it. Three rules turn one into the other.
1. The order is atomic number, and atomic number is protons. Hydrogen has one proton, helium two, lithium three, and so on to oganesson's 118. Every other fact on the table follows from that number, because the number of protons fixes the number of electrons, and the electrons decide the chemistry. This is Moseley's rule, and it is why argon (18) comes before potassium (19) even though argon is heavier.
2. A column is a family. Elements in the same group have the same number of electrons in their outer shell, so they react the same way. Lithium, sodium and potassium (group 1) all have one outer electron, all lose it easily, all react with water, and the reaction gets more violent going down. Fluorine, chlorine, bromine and iodine (group 17) all have seven outer electrons, all gain one, all form salts with sodium, and the reaction gets less violent going down. Helium, neon and argon (group 18) have full outer shells and do almost nothing. A student who knows group 1, group 17 and group 18 by behaviour can predict most school chemistry from the chart alone.
3. A row is a shell. Period 2 runs from lithium (one electron in the second shell) to neon (eight, the shell full); period 3 fills the third shell from sodium to argon. Across a period the atoms get smaller (more protons pulling the same shell in) and less metallic; down a group they get bigger (one more shell each time) and more metallic. Those two trends answer every "which is larger / more reactive / more metallic" question a paper can set.
Who modernized the periodic table
| Year | Who | What changed |
|---|---|---|
| 1869 | Dmitri Mendeleev, St Petersburg | Arranged the 63 known elements by atomic mass in a table with columns of similar behaviour, and left gaps for elements he predicted: eka-aluminium (gallium, found 1875), eka-boron (scandium, 1879), eka-silicon (germanium, 1886), with the properties he had written down |
| 1894 to 1898 | William Ramsay and colleagues | Discovered the noble gases, an entire group Mendeleev had not predicted, and it fitted at the end of each period |
| 1913 | Henry Moseley, Manchester and Oxford | Showed by X-ray spectra that each element has a whole-number charge on its nucleus, the atomic number, and that the table's order is atomic number, not mass; this resolved argon/potassium and tellurium/iodine and predicted the gaps at 43, 61, 72 and 75 |
| 1945 | Glenn Seaborg, Berkeley | Proposed that the actinides (89 to 103) form a series like the lanthanides and belong in a row below the table; the modern shape |
| 2016 | IUPAC | Named nihonium, moscovium, tennessine and oganesson, completing period 7 at 118 |
So "who modernized the periodic table" has a three-part answer: Mendeleev made it, Moseley put it in the right order, Seaborg gave it its shape.
The 11 symbols that do not match the name
Sodium is Na, potassium is K, iron is Fe, copper is Cu, silver is Ag, tin is Sn, antimony is Sb, tungsten is W, gold is Au, mercury is Hg and lead is Pb. All eleven come from Latin (natrium, kalium, ferrum, cuprum, argentum, stannum, stibium, wolfram, aurum, hydrargyrum, plumbum). Learn these eleven and every other symbol on the chart is the first letter or two of the English name.
What your class needs from the table
| Level | What to know from the chart | What to be able to do |
|---|---|---|
| CBSE Class 9 | The first 20 elements with symbols and atomic numbers; metals, non-metals, metalloids | Write symbols and atomic numbers from memory; place an element by its number |
| CBSE Class 10 and 11 | Groups 1, 2, 17 and 18 by behaviour; the trends across a period and down a group; the s, p, d and f blocks (Class 11) | Predict reactivity and atomic size; write electronic configurations by block |
| IGCSE and GCSE | Groups 1, 7 and 0 by name and reactions; the transition metals as a block; reading a data-book table | Explain group trends with electron shells; use the table to balance formulae |
| A-level, IB, AP | Periodicity of ionisation energy, atomic radius and electronegativity; the blocks; the lanthanide and actinide series | Explain the periodicity with shielding and nuclear charge; predict properties of an unknown element from its position |
How to learn it in a week
Day one, the first 20 in order, with the three-sentence trick for the first 30. Day two, the eleven Latin symbols. Day three, groups 1, 17 and 18 by behaviour. Day four, the two trends. Day five, cover the chart and draw the first four periods from memory; the gaps you leave are the revision list. Then keep the chart on the wall, because a table that is looked at every day stops being a thing to memorise. 1-on-1 online chemistry from Class 9 to A-level, with a tutor who holds a master's in chemistry, is on the chemistry page, and the first 30-minute class is free.
Questions parents ask
1Is there a free periodic table PDF I can print?
2Who modernized the periodic table?
3How many elements are in the periodic table?
4What do the colours on a periodic table mean?
See how we teach this, 1-on-1 online →
Shobha
Founder and lead tutor, Science with Shobha
Teaching maths, science and English to children online since 2018. 500+ students, 20+ tutors, families in nine countries.