5. A reaction in which them material that starts the reaction is also one of the products and can start another reaction is called a. An accelerator reaction
b. A moderator reaction
c. A shielding reaction
d. A chain reaction

a electronegativity decreases beacuse the size of nucleus is bigger.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.  

the correct answer would be b) volume versus temperature, because they are also directly proportional.