Four stock cards pair a proposed symbol for tin with a proton count: T with 22, Ti with 22, In with 49, and Sn with 50. Find the card using tin's correct symbol and enter the proton count printed on that card.
الإجابة الصحيحة
50
الشرح
Tin uses Sn, so the relevant stock card is the one carrying the proton count 50. Ti and In are symbols of other elements, while T is not the standardized symbol for tin.