Determine the number of valence electrons for each of the following: O
Cs
Ca
Se2-
Na+
C
N
Al
He

Chemical kinetics what was the rate of reaction in trial 3? choose the closest answer.

According to each substances heat of fusion, which of the items below requires more heat to be added per gram of substance to go from solid to liquid? silver sulfur water lead

Sally is making a model of a magnesium atom with an atomic mass number of 24 for her chemistry class. she has foam balls for the protons, neutrons, and electrons. she has added 6 neutrons to her model so far. how many more neutrons does she need to add to complete her neutral atom of magnesium?