Boron has two naturally occurring isotopes. Boron 10 abundance is 19.8%. Mass is 10.013 amu. Boron 11 Abundance is 80.2%. Mass is 11.009 amu. Calculate the average atomic mass of Boron.

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.

What is the correct lewis structure for chloroform chcl3

What conclusion can you draw from this experiment about the components of the black ink?