Explain how convection currents would affect the depth that which molten rocks are found

Iknow the answer to 13 is b and 14 is d. i just need to know why the correct answers are correct

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?

Voltaic cells produce a positive overall charge. what does this indicate? a. the reaction is likely to be endothermic. b. the reaction is spontaneous. c. the reaction is not likely to occur. d. the reaction is not spontaneous.