draw cross and dot diagrams to show bonding in the following compounds, sodium chloride Magnesium Oxide, ammonia, ethene, ethane, carbontetrachloride​

Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.

Consider the elements bromine and chlorine; which elements has a larger ionic radius ?

This drawing shows a human body system. what is the primary function of this body system?