The answer is B. A good way determine this is how far right the element is on the periodic table. The further right the element is, the more electronegative it is meaning it is more willing to accept an electron. This can be explained using the valence electrons and how many need to be added or removed to complete the octet. The further right you are, the easier it is for the element to just gain a few electrons instead of loose a bunch. Noble gases are the exception to this since they don't normally react though.
Explanation:
The more reactive element replaces less reactive element during chemical reaction.
Since, potassium is more reactive than beryllium. When potassium reacts with beryllium choride, it replaces beryllium and forms potassium chloride and produces beryllium.
3433Explanation:
the awser sucks and its not RIGHT