Answer
$CoSO_{4}.7H_{2}O$ is named Cobalt(II) sulfate heptahydrate.
Work Step by Step
$CoSO_{4}.7H_{2}O$ has its cation $Co^{2+}$, a charge of (II), its anion $SO_{4}^{2-}$ and 7 (hepta) water molecules of hydration. Hence, its name is cobalt (II) sulfate heptahydrate.