Which two particles are found in the center of an atom?
electrons and ions
protons and neutrons
protons and electrons
electrons and neutrons

Protons and neutrons

Explanation:

According to the accepted theory of the structure of an atom ( note it isn't 100% accurate) the center of the atom, or the nucleus, contains the protons and neutrons. Around the nucleus you have electrons, which are located in electron shells and orbit the nucleus in nearly circular elliptical orbits. They orbit the nucleus because they are attracted to the protons in the nucleus (opposite charged particles attract one another.)

! 55 !  

write a paragraph or story to explain the transformation between potential and kinetic energy as shown in your picture or model.  

you should have at least 5 complete sentences with a main idea and supporting details.  

you must include the following words:  

potential energy

kinetic energy

mechanical energy

conservation of energy

dude, this is hard lol : ))