Periodic Table Memory Tips for the Quiz

The first twenty, with a mnemonic

A sentence whose words start with the symbols does the job for the first ten: "Happy Henry Likes Beer But Could Not Obtain Food Nearby". Then "Naughty Mgpies Always Sing Perfect Songs Clearly Around King Carl" for 11 to 20. Silly sentences stick better than sensible ones; make your own if these do not.

Symbols that do not match the English name

These come from Latin or German names and are a favourite quiz question:

Hooks: Argentina was named for silver (Ag); a plumber once worked with lead pipes (Pb); "Au" is the start of "aurora", golden dawn; Hg is "hydr-argyrum", water-silver, which is exactly what mercury looks like.

Groups: the columns

Elements in the same column behave alike, and quiz questions lean on four groups:

• Group 1, the alkali metals: lithium, sodium, potassium, rubidium, caesium, francium. Soft, very reactive, react with water; reactivity increases down the group (caesium is the most violent). Hydrogen sits above them but is a gas and not a metal.
• Group 2, the alkaline earth metals: beryllium, magnesium, calcium, strontium, barium, radium. Less reactive than group 1; calcium and magnesium are the everyday ones.
• Group 17, the halogens: fluorine, chlorine, bromine, iodine, astatine. Reactive non-metals; at room temperature fluorine and chlorine are gases, bromine a liquid (one of only two liquid elements, with mercury), iodine a solid. Reactivity decreases down the group.
• Group 18, the noble gases: helium, neon, argon, krypton, xenon, radon. Unreactive gases with full outer shells; helium fills balloons, neon lights signs, argon fills light bulbs.

A mnemonic for the noble gases: "Helium Never Argues, Krypton Xenophobically Radiates Nothing".

Periods: the rows

The row number is the number of electron shells. Period 1 has only hydrogen and helium; periods 2 and 3 have eight elements each (lithium to neon, sodium to argon), which is why the first twenty elements fit neatly into three rows plus potassium and calcium starting the fourth. Atomic number increases left to right along a row and down the table, so the "atomic number of X" questions are counting questions once you know the layout.

Metals, non-metals and the staircase

Roughly three quarters of the elements are metals, filling the left and centre of the table. The non-metals cluster in the top right: hydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, selenium, the halogens and the noble gases. Between them runs a staircase of metalloids (boron, silicon, germanium, arsenic, antimony, tellurium) with properties of both. A question that asks "which of these is a non-metal" is usually answered by picking the element furthest to the top right.

Facts that come up again and again

• The lightest element is hydrogen; the most abundant in the universe is hydrogen; the most abundant in the Earth's crust is oxygen, then silicon.
• The only two elements liquid at room temperature are mercury and bromine.
• Carbon is the basis of organic chemistry and has atomic number 6; diamond and graphite are both carbon.
• Helium is the second lightest element and the one that makes voices squeaky; it is named after the Sun (helios), where it was first detected.
• Gold (Au, 79), silver (Ag, 47) and copper (Cu, 29) sit in the same column, group 11, which is why they share properties and were the coinage metals.
• Uranium (U, 92) is the heaviest element found in quantity in nature; elements beyond it are made in laboratories.

How to study

1. Learn the first twenty in order with the two sentences, then test yourself backwards from 20 to 1.
2. Learn the eleven mismatched symbols as a table.
3. Learn the four named groups as sets, with one everyday fact about each.
4. Play the quiz; after each answer read the explanation, which usually names the group or the origin of the symbol.
5. Repeat the quiz the next day: the questions change, the patterns do not.

Glossary

• Atomic number: the number of protons in an atom; the elements are ordered by it.
• Symbol: the one- or two-letter abbreviation, sometimes from Latin.
• Group: a column of the table; elements in a group behave alike.
• Period: a row of the table; the row number is the number of electron shells.
• Noble gas: a group 18 element, unreactive because its outer shell is full.
• Halogen: a group 17 element, a reactive non-metal.
• Metalloid: an element on the staircase between metals and non-metals.