Answer
(a) $^{3}H$
(b) $^{18}O^+$
Work Step by Step
(a) If there is one proton, then it is hydrogen.
If there are two neutrons and one proton, then there are three nucleons.
If there is one electron, then the charge is neutral.
We can write the symbol for this atom:
$^{3}H$
(b) If there are eight protons, then it is oxygen.
If there are ten neutrons and eight protons, then there are eighteen nucleons.
If there are seven electrons, then the charge is +1.
We can write the symbol for this ion:
$^{18}O^+$
