BIOL 112 Lecture Notes - Lecture 1: Mass Number, Noble Gas, Radiocarbon Dating

• School: McGill University
• Department: Biology
• Course: BIOL 112
• Professor: Frieder Schoeck

Document Summary

Mass number (# of protons + neutrons) (aka dalton, d (molecular weight)) Actual mass number cane slightly off ex. Hydrogen, sodium, magnesium, carbon, nitrogen, oxygen, phosphorus, sulphur, chlorine > important elements for biology. Columns have same # of valence e- The only important element for chemical bonding is the valence (outer) electrons: have roughly the same chemical behaviour. Electrons paired in groups of 2 (orbitals), orbitals always contains either 1 or 2 electrons and are very important for explaining the chemical bonding between the atoms. Always try to ll the orbitals to become stable (explains quantum mechanics) Neon- very stable, very inert, because its outermost shell is completely lled and all of its outer orbitals are lled with electrons. Hydrogen only has 1 electrons therefore very likely to form chemical bonds to gain. Covalent bond= new stable orbital lled with 2 electrons (1 from each atom: each covalent bond has certain strength, length and angle.