CEM 141 MSU Exam 3 Revision Questions Fully Solved.

Ionization Energy - Answer energy required to remove an electron from an atom in the gas phase Left Side Electrons - Answer have weaker attractions to remove electrons *easier to remove electrons from the left side of the table than the right side* Does it take MORE or LESS energy to remove an electron from Li than from Na? - Answer MORE Why? Because as we move down a group, the orbitals become larger and weaker. While going across the effective nuclear charge increases. (holds onto the electrons tighter) Big Bang evidence - Answer universe is expanding (red shift) Where do atoms come from? - Answer The Big Bang What were elements formed by? - Answer Nuclear reactions Chemical reactions - Answer involve rearrangements of valence electrons *the element undergoing a chemical reaction does not ever change* Ionization energies are affected by - Answer -size of an atom -size of positive charge Periodic Trends - Answer -small atoms have higher ionization energies -they are inversely related Atomic Radius Decreases ----> Ionization energy increases - Answer when the radius decreases, it pulls the electrons closer. decreasing the size of an atom Nuclear Reactions - Answer Fusion and Fission Fusion - Answer two lighter nuclei combines to form a heavier nucleus (energy released)