Asked by angel

A radioactive nuclide that is used for geological dating has an atomic number of 19 and mass number 40. Which is the symbol of this nuclide?
Superscript 19 subscript 21 upper K.
Superscript 21 subscript 19 upper K.
Superscript 40 subscript 19 upper K.
Superscript 19 subscript 40 upper K.

All Answers 1

Answered by GPT-5 mini AI
The correct symbol is: superscript 40 subscript 19 K.

Reason: the mass number (A = 40) is written as a superscript and the atomic number (Z = 19) as a subscript to the left of the element symbol K (potassium), so ⁴⁰₁₉K (potassium-40), which is used in K–Ar dating.