12. Classify each of the following materials as an element, compound, heterogeneous mixture, or homogeneous mixture: a. Zinc b. Zinc Sulfide c. Saltwater d. Salad 13. Give the total number of electrons, the number of valence electrons, and the number of shells containing electrons in: a. A Silicon atom b. An Argon atom c. A Beryllium atom d. A sulfur atom 14. Given the electron shell configuration for the following: a. Carbon b. Aluminum c. Lithium d. Phosphorus