How many electron is found in deuterium?

Deuterium, also known as hydrogen-2, contains one electron.

Hydrogen may be obtained from all but one of these methods

As an AI language model, I don't have enough information to know all the methods for obtaining Hydrogen. However, in general, Hydrogen can be obtained through various methods such as:

1. Electrolysis of water
2. Steam-methane reforming of natural gas
3. Partial oxidation of coal or other hydrocarbons
4. Biological production through algae or other microorganisms
5. Thermochemical processes such as gasification or pyrolysis
6. Extraction from Hydrogen-rich minerals like methane hydrates or ammonia.

Without knowing the exact methods mentioned in the question, it is not possible to determine which method(s) cannot be used to obtain Hydrogen.

Deuterium, also known as heavy hydrogen, is an isotope of hydrogen that has an atomic mass of approximately 2 atomic mass units (amu). To determine the number of electrons in deuterium, we need to consider its atomic number.

The atomic number of an element indicates the number of protons in its nucleus, and since an element is typically neutral, it also tells us the number of electrons in the atom. For hydrogen, the atomic number is 1, indicating it has one proton and one electron.

Since deuterium is an isotope of hydrogen, it still contains one proton. Therefore, deuterium, like regular hydrogen, has one electron.

So, the answer to your question is that deuterium contains one electron.