CEM 141 MSU Exam 3 Latest Update Graded A+

CEM 141 MSU Exam 3 Latest Update Graded A+ Ionization Energy energy required to remove an electron from an atom in the gas phase Left Side Electrons 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? 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 universe is expanding (red shift) Where do atoms come from? The Big Bang What were elements formed by? Nuclear reactions Chemical reactions involve rearrangements of valence electrons *the element undergoing a chemical reaction does not ever change* Ionization energies are affected by -size of an atom -size of positive charge Periodic Trends -small atoms have higher ionization energies -they are inversely related Atomic Radius Decreases ----> Ionization energy increases when the radius decreases, it pulls the electrons closer. decreasing the size of an atom Nuclear Reactions Fusion and Fission Fusion two lighter nuclei combines to form a heavier nucleus (energy released) Fission a heavier nucleus is broken a part to form lighter, more stable nuclei energy Atomic # = # of protons Atomic mass = what's left over Do isolated atoms or molecules have melting or boiling points? No Do isolated atoms or molecules exist in a state (solid, liquid, gas)? No Why do bonds form between atoms? because valence electrons are attracted to the nuclei of other atoms Covalent Bonds two hydrogen atoms interact and form a covalent bond What properties do metals have? -hard -conduct electricity -shiny -react w/water -malleable Bonding in Metals atomic orbitals combine with each other to form molecular orbitals Covalent bonds hold atoms together within.. molecules Molecular interactions hold atoms together between...