1. Alkali metals:

- Hydrogen, sodium, and rubidium are all alkali metals. This means they belong to Group 1 of the periodic table.

2. Highly reactive:

- Alkali metals are known for their high reactivity. They readily lose their outermost electron (valence electron) to form positive ions (cations). This high reactivity is due to their low ionization energy.

3. Formation of basic oxides and hydroxides:

- When alkali metals react with oxygen, they form basic oxides (e.g., Na2O, Rb2O). Similarly, when they react with water, they form strongly basic hydroxides (e.g., NaOH, RbOH).

4. Low ionization energy:

- Alkali metals have low ionization energies because the valence electron is loosely bound to the nucleus. This makes it easy for them to lose this electron, resulting in the formation of positively charged ions.

5. Shiny and silvery appearance:

- Hydrogen, sodium, and rubidium all have a shiny and silvery appearance due to their metallic nature.

6. Good conductors of electricity and heat:

- Alkali metals are excellent conductors of electricity and heat. This property is a result of their loosely bound valence electrons, which can move freely within the metal's crystal lattice.

It's important to note that while hydrogen, sodium, and rubidium share these similarities as alkali metals, they also exhibit unique properties and characteristics that distinguish them from each other.