CHEM 105 Lecture 6: 6- Lecture Monday, September 10th
Document Summary
Nothing in group trends (properties of elements in the same column) makes sense except in the light of electron energy shells. Nothing in the period trends (properties of elements in the same row) makes sense except in the light of increasing nuclear charge. A compound is matter composed of more than one element. An ionic compound (that is, a salt) is: Have at least one metal ion and one nonmetal ion. A covalent compound (that is, a molecule) is: A covalent compound with at least one carbon. Fact: noble gases, such as helium, neon, and argon are inert; they undergo few, if any, chemical reactions. Theory: the inertness of noble gases results from their electron structures; each (except for helium) has an octet of electrons in its outermost shell. Deduction: elements become less reactive when they alter their electron structures to that of a noble gas.
