Complete the exercises below. Which of the following statements are true? a. Si can form an ion with six fluorine atoms, SiF₆²⁻, whereas carbon cannot. b. Si can form three stable compounds containing two Si atoms each, Si₂H₂, Si₂H₄, and Si₂H₆. c. In HNO₃ and H₃PO₄, the central atoms, N and P, have different oxidation states. d. S is more electronegative than Se.

Ionic compounds form when atoms transfer electrons, resulting in charged ions. Silicon (Si) can form a hexafluorosilicate ion, SiF₆²⁻, by coordinating with six fluoride ions, which is a characteristic of its ability to expand its coordination number. In contrast, carbon typically forms covalent bonds and does not have the same capacity for coordination with multiple anions.

Silicon can form various stable compounds, including silanes like Si₂H₂, Si₂H₄, and Si₂H₆, which are characterized by different hydrogen saturation levels. These compounds illustrate silicon's ability to form multiple bonds and its versatility in bonding, which is distinct from carbon's bonding behavior in similar compounds.

Oxidation states indicate the degree of oxidation of an atom in a compound, reflecting the number of electrons lost or gained. In HNO₃ and H₃PO₄, nitrogen (N) and phosphorus (P) exhibit different oxidation states due to their differing positions in the periodic table. Additionally, electronegativity is a measure of an atom's ability to attract electrons; sulfur (S) is more electronegative than selenium (Se), influencing their chemical behavior and reactivity.