Chemical symbol

Columns: Chemical symbol | Name | Atomic number | Origin of symbol
Ac | Actinium | 89 | From the Greek aktinos . Name restricted at one time to Ac , an isotope of actinium . This named isotope later became the official name for element 89 | AcA | Actinium A | 84 | From actinium and A. Placeholder name given at one time to Po , an isotope of polonium identified in the decay chain of actinium | AcB | Actinium B | 82 | From actinium and B. Placeholder name given at one time to Pb , an isotope of lead identified in the decay chain of actinium | AcC | Actinium C | 83 | From actinium and C. Placeholder name given at one time to Bi , an isotope of bismuth identified in the decay chain of actinium | AcC ' | Actinium C ' | 84 | From actinium and C ' . Placeholder name given at one time to Po , an isotope of polonium identified in the decay chain of actinium | AcC | Actinium C | 81 | From actinium and C . Placeholder name given at one time to Tl , an isotope of thallium identified in the decay chain of actinium | AcK | Actinium K | 87 | Name given at one time to Fr , an isotope of francium identified in the decay chain of actinium

Example questions:
What is the named isotope 's chemical symbol for the element first isolated by French chemist André-Louis Debierne in 1899 ? | What is the named isotope 's chemical symbol for the element also known as heavy hydrogen ? | Which element has a named isotope symbol derived from a number with religious and spiritual significance in many cultures ? | What is the named isotope 's chemical symbol for the sixth element in group 2 of the periodic table ?

Answers:
Ac | D | Deuterium | Ra