Answer
(a) $_{58}^{140}Ce$
(b) $_{27}^{60}Co$
Work Step by Step
1. Use a periodic table to find the symbol for the element with the indicated atomic number "Z".
(a) The element with atomic number equal to 58 is Caesium (Cesium), whose symbol is "Ce".
(b)The element with atomic number equal to 27 is Cobalt, whose symbol is "Co".
2. Write the atomic number (Z) on the bottom left and the mass of the element (A) on the top left of the symbol.
(a) $_{58}^{140}Ce$
(b) $_{27}^{60}Co$
