A fictitious element X has an average atomic mass of 122.224 u.122.224 u. Element X has two naturally occurring isotopes. The most abundant isotope has an isotopic mass of 121.673 u121.673 u and a relative abundance of 60.92%.60.92%. Calculate the isotopic mass of the least abundant isotope.

answer: the rate of diffusion increases with increase in temperature.

increase in temperature, increases the molecular/particles speed (kinetic energy. diffusion means movement of particles through the material.

generally, the heavier the particle the more it interacts with the environment and more the temperature matters. so higher temperature results in higher diffusion.

i think it's c. if you look search electronic symbol on google and then click on wiki it shows you a

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.