Answer
a. $_{15}^{31}P$
b. $_{35}^{80}Br$
c.$_{50}^{122}Sn$
d.$_{17}^{35}Cl$
e.$_{80}^{202}Hg$
Work Step by Step
To answer this question you must study topic 4.4 ' Atomic number and Mass number' on page 114 and topic 4.5 ' Isotopes and Atomic Mass' on page 117.
a. the mass number is given by ' number of neutrons + number of protons' (15+16=31) and it goes above the element $^{31}P$. The atomic number (15 protons) goes below the element $_{15}^{31}P$.
