Which rule concerning oxidation numbers is NOT true? A. Fluorine always has an oxidation number of –1 in molecules that contain two or more types of atoms.
B. Oxygen has an oxidation number of –2 in molecules that contain two or more types of atoms.
C. If all else fails, assume that the atom’s oxidation number is the same as what it would take on in an ionic compound.
D. Reduction is the process by which an atom gains electrons.
E. Oxidation is the process by which an atom gains electrons.

12. complete each of the following word equations for synthesis reactions. a. sodium + oxygen -> b. magnesium + fluorine -> 13. complete and balance the equations for the decomposition reactions. a. hgo -> [with the triangle heat symbol above the arrow] b. h2o(l) -> [with "electricity" written above the arrow]

There are main groups in the modern periodic table of elements

Agroup of students is studying convection current. they fill two identical balloons with the same amount of helium. one balloon is placed in a freezer and the other is in an area with warm air. after 10 minutes, the balloon are released from a height of 1 meter. which of the following to the students most likely observe? a) the warm balloon expands and rises. the cold balloon shrinks and sinks b) the balloon both rise. the cold balloon is larger than the warm balloon c) the cold balloon expands and rises. the warm balloon shrinks and sinks d) the balloon rise at the same rate. both balloons are the same size