Question 1: What are valence electrons, and how are they related to the way atoms react? Question 2: Explain the "magic number" of helium and the other elements on the periodic table in terms of their valence electrons. What happens when an element reaches this "magic number?"

1:The outermost electrons -- the valence electrons -- are able to interact with other atoms, and, depending on how those electrons interact with other the atoms, either an ionic or covalent bond is formed, and the atoms fuse together to form a molecule.

2:Magic number, in physics, in the shell models of both atomic and nuclear structure, ... The magic numbers for atoms are 2, 10, 18, 36, 54, and 86, corresponding to the total number of electrons in filled electron shells. ... In the chemical elements of atomic number 17 to 19, for example, the chloride ion (Cl−).

Explanation:

answer 1) In chemistry and physics, a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.

Explanation:

I dont know the second one

a compound is a molecule made of atoms from different elements.

a. by the combination of an unlimited number of elements