Which describes how chemical changes are different from physical changes? (2 points) a Chemical changes can be measured, but physical changes cannot. b Chemical changes involve the formation of a new substance. c Chemical changes release energy, but physical changes absorb energy. d Chemical changes cannot be caused by oxygen.

Which of the following elements would you expect to have the highest ionization energy value, and why? a. chlorine (cl), because it has a low effective nuclear charge and large radius b. fluorine (f), because it has a large radius and naturally forms a negative ion c. lithium (li), because it has a small radius and naturally forms a positive ion d. neon (ne), because it has a high effective nuclear charge and small radius