The Periodic Table: Elements, Shells and Ions

The Periodic Table — Key Terms

Key concepts in English, with te reo Māori, Chinese (Simplified) and Korean.

English	Te reo Māori	中文（简体）	한국어	What it means on this page
Periodic table	taka pūmotu	元素周期表	주기율표	The elements arranged in order of increasing atomic (proton) number, in rows called periods and columns called groups.
Element	pūmotu	元素	원소	A substance made of atoms that all have the same number of protons.
Atom	ngota	原子	원자	The smallest particle of an element: a nucleus of protons and neutrons, surrounded by electrons.
Nucleus	karihi	原子核	원자핵	The tiny, dense centre of an atom, made of protons and neutrons.
Proton	iraoho	质子	양성자	A positively charged particle in the nucleus (relative mass 1, relative charge +1).
Neutron	iramoe	中子	중성자	An uncharged particle in the nucleus (relative mass 1, relative charge 0).
Electron	irahiko	电子	전자	A negatively charged particle outside the nucleus (relative mass 1/1836, relative charge −1).
Atomic number	tau iraoho	原子序数	원자 번호	The number of protons in the nucleus of an atom (also called the proton number). It identifies the element.
Relative atomic mass	no attested term	相对原子质量	상대 원자 질량	The weighted average mass of an atom of an element, compared with one twelfth of the mass of an atom of carbon-12 (Aᵣ).
Isotope	kanoirite	同位素	동위 원소	Atoms of the same element with the same number of protons but different numbers of neutrons.
Electron shell	no attested term	电子层	전자 껍질	A main energy level that electrons occupy (n = 1, 2, 3 …); shell n holds up to 2n² electrons.
Subshell	no attested term	电子亚层	부껍질	Part of a shell: s, p, d or f, holding up to 2, 6, 10 or 14 electrons.
Orbital	no attested term	原子轨道	오비탈	A region of space around the nucleus that can hold up to two electrons, with opposite spins.
Electron configuration	no attested term	电子排布	전자 배치	How an atom's electrons are arranged in shells, subshells and orbitals, for example 1s² 2s² 2p⁶ 3s¹ for sodium.
Valence electron	irahiko hohe	价电子	원자가 전자	An electron in the outer shell of an atom: the electrons involved in bonding.
Period	no attested term	周期	주기	A row of the periodic table. Elements in the same period have the same number of occupied electron shells.
Group	no attested term	族	족	A column of the periodic table. Elements in a group have the same number of outer-shell electrons, so they react in similar ways.
Ion	katote	离子	이온	An atom or group of atoms with an electrical charge, because it has lost or gained electrons.
Cation	no attested term	阳离子	양이온	A positive ion, formed when an atom loses electrons (metals form cations).
Anion	no attested term	阴离子	음이온	A negative ion, formed when an atom gains electrons (non-metals form anions).
First ionisation energy	no attested term	第一电离能	제1 이온화 에너지	The energy needed to remove one electron from each atom in one mole of gaseous atoms, forming one mole of gaseous 1+ ions.
Electronegativity	no attested term	电负性	전기 음성도	The power of an atom to attract the pair of electrons in a covalent bond towards itself (Pauling scale).
Metal	konganuku	金属	금속	An element that is usually shiny, malleable and a good conductor of heat and electricity, and forms positive ions.
Non-metal	konu-kore	非金属	비금속	An element that is usually a poor conductor, and forms negative ions or covalent bonds.
Metalloid	haukonu	类金属	준금속	An element with properties between those of metals and non-metals, such as silicon and germanium.
Transition element	no attested term	过渡元素	전이 원소	A d-block element that forms one or more stable ions with an incomplete d subshell.
Alkali metal	no attested term	碱金属	알칼리 금속	An element of group 1 (except hydrogen): a soft, reactive metal whose atoms lose one electron to form 1+ ions.
Halogen	no attested term	卤素	할로젠	An element of group 17: a reactive non-metal whose atoms gain one electron to form 1− ions.
Noble gas	no attested term	稀有气体	비활성 기체	An element of group 18, with a full outer shell of electrons, which makes it very unreactive.
Oxidation state	no attested term	氧化态	산화 상태	The charge an atom would have if all its bonds were ionic; it shows how many electrons it has lost or gained (also oxidation number).

On the te reo Māori column. Terms marked as gaps have no attested equivalent in the sources checked — Karaitiana Taiuru's Dictionary of Māori Computer and Social Media Terms, Paekupu, the Reserve Bank's te reo financial glossary, NZQA and Te Aka. No coinage is printed as though it were established; where a class needs one, commission it from Te Taura Whiri i te Reo Māori and credit the translator. Te reo Māori is not italicised and takes no plural "s".