Hydrogen-like species are atoms or ions that have only one electron and are similar in structure to hydrogen. They have a single electron orbiting a nucleus with a positive charge.

Hydrogen-like species:

1) He2:
He2 is not a hydrogen-like species because it consists of two helium atoms bonded together. Each helium atom has two electrons, so the total number of electrons in He2 is four. It does not have the characteristic structure of a hydrogen-like species with a single electron.

2) Be3:
Be3 is not a hydrogen-like species because it consists of three beryllium atoms bonded together. Each beryllium atom has four electrons, so the total number of electrons in Be3 is twelve. It does not have the characteristic structure of a hydrogen-like species with a single electron.

3) Li:
Li is a hydrogen-like species because it is a lithium atom with atomic number 3. It has three protons in the nucleus and three electrons. The single electron in the outermost shell of Li can be considered similar to the structure of hydrogen.

4) H:
H is a hydrogen-like species because it is a hydrogen atom with atomic number 1. It consists of a single proton in the nucleus and a single electron orbiting around it. The structure of hydrogen is the basis for defining hydrogen-like species.

In summary, out of the given options, only Li and H are hydrogen-like species. Li has three electrons, while H has one electron. The key characteristic of a hydrogen-like species is that it consists of a single electron orbiting a positively charged nucleus, similar to the structure of hydrogen.

Hydrogen because one electron in outermost orbit.