Answer:
Two nonmetals that can be combined with three H hydrogens are nitrogen N and phosphorus P, which form respective NH₃ and PH₃ compounds.
Step-by-step explanation:
Valencia electrons are the electrons found in the last electronic layer (called valence orbitals). These electrons are what determine the ability of the atom to form bonds. When an element joins another, it does so through its valence electrons. It is also possible to say that these electrons are the electrons furthest from the nucleus of the atom, which is why they participate in chemical reactions.
And electrons, in addition to determining the reactivity of the elements, allows to determine their location in the Periodic Table. All elements of the same group have the same number of valence electrons (This does not occur in transition metals). The valence electrons increase in number as one advances in a period. Then, at the beginning of the new period, the number decreases to one and begins to increase again.
So, in summary, those elements that belong to a group have the same number of electrons in their last or last layers, and the group number indicates the electronic configuration of their last layer, varying only the period of the element.
Then, hydrogen H is usually classified as a nonmetal that is located in group 1. This means that 1 electron in its last layer. This electron reacts with other elements. If you have 3 H hydrogens, then you will have 3 electrons that the nonmetal element to which the H will attach will accept.
On the other hand, the covalent bond is the chemical bond between atoms where electrons are shared, forming a molecule. Covalent bonds are established between non-metallic elements, such as hydrogen H, oxygen O and chlorine Cl. These elements have many electrons in their outermost level (valence electrons) and have a tendency to gain electrons to acquire the stability of the electronic structure of noble gas. The shared electron pair is common to the two atoms and holds them together.
Then, the union between the three H hydrogens and another nonmetal will be covalent. And the nonmetal element must have 5 electrons in its last layer, in order to share an electron with each of the hydrogens (three in total) and thus have 8 electrons in its last layer and be stable.
This leads to say that the nonmetal element belongs to group 15 (V A) since in that group the elements have 5 electrons in their last layer. Two nonmetals belonging to that group are nitrogen N and phosphorus P, which form respective NH₃ and PH₃ compounds with hydrogen.