What is the producing of a physical, conceptual, or mathematical representation of a real phenomenon that is difficult to observe directly?

Which type of bonding involves the complete transfer of a valence electron from a less electrogrative atom to a more electronegative one

Why does the sun appear to be the brightest star in the sky? a- its apparent brightness is much greater than other stars. b- it burns more gas, making it brighter than any other star. c- it is the largest star in the galaxy, so it is the brightest star. d- its relative distance to earth is closer than the other stars.

For each of the compounds below, show that the charges on the ions add up to zero. a. kbr b. cao c. li(2)o d. cacl(2) e. alcl(3)