| HELIUM | Atom of this element created by the reaction in 9 Across |
| ESTER | Fragrant compound, used in soap-making, created by the reaction of an alcohol and an acid |
| IRON | An element created by nucleosynthesis and present in the body's haemoglobin; or, an appliance used for pressing laundered linen (4) |
| BERKELIUM | Artificial radioactive element created in California in 1949 |
| BORON | Element created to absorb oxygen |
| SULPHUR | In the 19th century, most of the world's supply of this element came from Sicily |
| NITROGEN | This element makes up about four-fifths of Earth's atmosphere. Plants called legumes can convert the atmospheric form of this element directly into useful compounds. |
| AMMONIA | Colourless pungent gas composed of one atom of nitrogen bonded to three atoms of hydrogen, chiefly used in the manufacture of fertilisers and nitric acid (7) |
| OXIDE | Binary compound formed by the reaction of oxygen with another element (5) |
| LEAD | The symbol of this element is derived from plumbum in Latin. |
| ESTERS | Organic compounds formed by the reaction between an alcohol and an acid, with the elimination of water (6) |
| ETHER | Colourless volatile highly-flammable liquid made by the reaction of sulphuric acid with ethanol |
| FUSION | The reaction that powers the Sun and other stars, where two atoms of hydrogen combine |
| ISOTOPE | As knowledge of nuclear physics increased this term was needed to describe an atom of the same element with a different number of neutrons |
| CARBON | Organic chemistry is based on the study of this element, which also makes up coal, petroleum, natural gas, and all plant and animal tissues. |
| MAGNESIUM | Carbonates of this element and calcium create hard water |
| ZINC | Flowers of this element are antiseptic (4) |
| COMPONENT | Con men opt for a poorly made version of this element |
| DUMBSTATUES | In 3.7, Buckingham tells Richard of the reaction the public gave him when he said, "Cry, God save Richard, England's royal king? What was the crowd's initial reaction like? |
| CATALYSIS | Reduction of the reaction times of a city lass in transit (9) |
