CHEM 201DL Chapter Notes - Chapter 1: Valence Electron, Covalent Bond, Ionic Bonding
Document Summary
Compounds associated w/ living things generally concern carbon. Jacob berzelius - coined the term organic, substances isolated from living things. Friedrich wohler - isolated urea, discovery removed barrier between organic and inorganic chemistry. Holds together molecules, due to behavior of electrons. Octet rule - tendency of atoms to gain or lose valence electrons to form ions with the noble-gas configuration. Ionic compounds dissociate into free ions, as shown by conductivity. The same in all directions -- no preferred orientation in space. Electron pair that is shared between bonded atoms. Sum of all shared and unshared valence electrons around each atom in many stable covalent compounds is eight (or 2 for hydrogen) In covalent compounds, shared electrons are counted twice. twice. Formal charge = group # - valence electron count. Valence electron count = unshared electrons + 1/2 bonding electrons. Sum of formal charges equals total charge of ion. Hydrogen can share no more than two electrons.
