True or false. elements in the same period have the same number of valence electrons

Suppose you mast out 6.39 g of water how many moles would you have

Emission of light from an atom occurs when an electron drops from a higher to a lower energy level jumps from a lower to a higher energ) level moves within its atomic orbital falls into the nucleus

A hydrogen bond is: a. a strong attraction between hydrogen and another atom. b. a bond between a hydrogen atom already covalently bound to one atom and made partially negative by unequal electron sharing with another atom. c.

The major source of aluminum in the world this bauxite (mostly aluminum oxide). It's thermal decomposition can be represented by: Al2 O3 (s) - > 2 Al (s) + 3/2 O2 (g) ΔH rxn =

In burning gasoline the products are

What do igneous rocks form from? (20pts!)

A gas at STP has a volume of 1.0 liter. If the pressure is doubled and the temperature remains constant, the new volume of the gas will be ... ?

Combustion analysis of toluene, a common organic solvent, gives 8.20 mg of co2 and 1.92 mg of h2o. if the compound contains only carbon and hydrogen, what is its empirical formula?

Why does the moon have phases? What are the four main phases of the moon? How long does it take to change from one to another?

How many atoms are in 1/2 mole of calcium