Oxidation state of carbon + Oxidation state of hydrogen + Oxidation state of germanium = 0
Carbon has an oxidation state of +4, and the oxidation state of hydrogen is -3 (as calculated above).
—
+4 + (-3) + x = 0
Simplified:
1 + x = 0
x = -1
Therefore, the oxidation state of germanium (Ge) in CH3GeH3 is -1.