To view individual hydrogen atoms under an electron microscope, it is not possible to directly separate hydrogen atoms from hydrogen molecules (H2). However, there are alternative techniques that can be used to visualize individual atoms.
One common method is to use a technique called field ion microscopy (FIM). In FIM, a sample of hydrogen gas (H2) is adsorbed onto a metallic surface such as tungsten. By applying a high electric field to the tungsten surface, the hydrogen atoms at the surface can be ionized and ejected as ions. These ions can then be detected and imaged using an electron microscope, allowing the visualization of individual hydrogen atoms.
Another technique is scanning tunneling microscopy (STM). In STM, a sharp metallic probe is brought into close proximity with the sample surface. By applying a voltage between the probe and the surface, electrons can tunnel between them. By scanning the probe across the surface and monitoring the tunneling current, the surface topography can be mapped, and individual atoms, including hydrogen atoms, can be imaged.
It's important to note that the direct visualization of hydrogen atoms is challenging due to their small size. Additionally, in many cases, hydrogen atoms can be highly mobile on surfaces, making their imaging more difficult. However, with advanced microscopy techniques and careful experimental conditions, it is possible to study hydrogen atoms indirectly by observing their effects on the surrounding environment or by using imaging methods that provide indirect evidence of their presence.