Which of the following elements will form a cation with a +2 charge?

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.

Sharon reads two different articles about avocados. the first article, in a weight loss magazine, claims that avocados are unhealthy because they are high in fat. the second article, in an annual publication from a doctors' group, claims that the fat in avocados is a type that is good for the heart.

In a synthesis reaction, one reactant contains 256 j of chemical energy, and one reactant contains 328 j of chemical energy. the product contains 407 j of chemical energy. because energy is conserved, what energy change occurs during the reaction? a. 177 j of energy is released. b. 335 j of energy is absorbed. c. 177 j of energy is absorbed. d. 335 j of energy is released.