Use the drop-down menus to complete each sentence. The number of half-lives changes. This is the variable. The number of radioactive atoms changes due to the number of half-lives. The number of radioactive atoms is therefore the variable.

If an atom contains 11 protons in its nucleus, predict the element with the atomic number and electronic configuration. will the number of electrons remain the same during the chemical reaction in such an atom? explain.

Abowling ball rolling down the lane toward the pins has gravitational potential energy. a. no b. a lot of c. a little

Which type of reaction is shown in this energy diagram? energy products activation energy reactants time o a. endothermic, because energy is released to the surroundings o b. exothermic, because energy is absorbed from the surroundings o c. exothermic, because energy is released to the surroundings o d. endothermic, because energy is absorbed from the surroundings