Consider the two electron arrangements for neutral atoms A and B. The outer electron of atom B has moved to a higher energy state. What could cause this difference? A - 1s22s22p63s1
B - 1s22s22p65s1

Electrons were knocked out of B by high energy particles.
Atom B has lost energy, perhaps by cooling.
Atom B has absorbed energy, perhaps by heating.

chemistry sucks a**

explanation:

the food using pesticides in the future will harm you by giving you diseases like cancer or something since they have things that we should not eat in it like chemicals or pesticides. that is why organic food is more expensive because they take the time to make it right and healthy for you to eat.

explanation:

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.