The data table below shows elements Xx, Yy, and Zz from the same group on the periodic table. What is the most likely atomic radius of element Yy? A. 103 pm
B. 127 pm
C. 166 pm
D. 185 pm

answer; 4 electrons;

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.