What does polar mean in chemical bonding?

What is the molar mass of babr2? a. 217.2 g/mol b. 297.1 g/mol c. 354.5 g/mol d. 434.4 g/mol

What semimetal can form four single covalent bonds.

Silver tarnishes as silver metal reacts with hydrogen sulfide, h2s, in the air. in this reaction, dark silver sulfide, au2s, covers the surface of silver. when silver is polished, this coating of silver sulfide can be removed from the surface. this makes the silver shiny again. enter the coefficients that balance the tarnishing reaction equation. (type 1 for no coefficient.)