Using only the elements Ca, Cl, and Si, give formulas for the following. (b) A molecular compound with polar covalent bonds that obeys the octet rule and has no formal charges

Polar covalent bonds occur when two atoms share electrons unequally due to differences in electronegativity. In such bonds, the atom with higher electronegativity attracts the shared electrons more strongly, resulting in a partial negative charge on that atom and a partial positive charge on the other. This uneven distribution of charge creates a dipole moment, making the molecule polar.

The octet rule is a chemical principle stating that atoms tend to bond in such a way that they each have eight electrons in their valence shell, achieving a stable electron configuration similar to that of noble gases. This rule is particularly relevant for main group elements and guides the formation of covalent bonds, ensuring that atoms share or transfer electrons to fulfill this requirement.

Formal charge is a theoretical charge assigned to an atom in a molecule, calculated based on the number of valence electrons, the number of non-bonding electrons, and half the number of bonding electrons. It helps in determining the most stable Lewis structure for a molecule. A stable molecular structure typically has formal charges close to zero, indicating that the distribution of electrons is balanced and that the molecule is energetically favorable.