Answer:
electroluminescence is a production of light by the flow of electrons, as within certain crystals. An example is at most resataurants with a bright sign that either says open or closed.
Explanation:
Assuming that the ammonium sulfide formula is (NH4)2S then you can see that there are 2 nitrogen, 8 hydrogen and 2 sulfur atoms for every ammonium sulfide. If the amount of ammonium sulfide is 8.9 moles, then the number of hydrogen atoms should be: 8/1 * 8.9 mol= 71.2 moles
A large atom means that the radius would be large, meaning that the effective nuclear charge is low, therefore a lower electronegativity based on the periodic table. A smaller atom would mean the opposite, therefore a higher electronegativity. This combination would mean that the new molecule is polar.
Also, to answer your question, it would be most likely different from both atoms, as size doesn't really matter in a compound's properties.
3rd one:
it is very reactive because it does not have a full Valence shell.
this is because it's in group 1 so it has one electron in its outer shell, and it wants to have a full outer shell ( which it can gain by losing the electron in a reaction).
Hope this helps :)
Reactants would be the missing word in the sentence because they make up the products in a chemical reaction