CH 220 1st Edition Lecture 1 Outline of Current Lecture I. What is Organic Chemistry?II. Origins of Organic ChemistryIII. Atomic structure, atomic number and atomic massIV. OrbitalsV. Chemical bondsCurrent LectureI. What is Organic Chemistry?All living things are made of organic chemicals (proteins that make up hair, DNA, foods, medicines)Chemical structures may look different but they have similaritiesChemical families have similar uses, for instance gasoline and propane are ‘related’ and are both used for fuelII. Origins of Organic ChemistryFoundations of organic chemistry from the mid 1700s, with compounds being obtained from plantsIt was thought that organic compounds contained a ‘vital force’ because they were from living sourcesMid-1800s – it was identified that there were no fundamental differences between organic and inorganic substances90% of organic compounds contain carbonThis class will focus on H, C, N, O, F, Cl, Br, I (and sometimes P & S)III. Atomic structure, atomic number and atomic massThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Atomic Structure:-Positively charged nucleus that contains protons and neutrons-Negatively charged electrons are in a ‘cloud’ around the nucleus-Diameter is around 200 picometers (pm)Atomic Number:-Often written as (Z), is the number of protons in the atom’s nucleus-Atoms of a given element always have the same atomic numberAtomic Mass:-Often written as (A), is the number of protons plus neutrons-Isotopes are atoms of the same element that have different numbers of neutrons and therefore different mass numbers – although we won’t be covering isotopes in this classIV.OrbitalsQuantum mechanics describes electron energies and locationsOrbitals describe where electrons are most likely to be with reference to the nucleus, it is a ‘probable’ area and not a definite oneThere are four different kids of orbitals and they are denoted s, p, d, and f (we will be mainly focusing on s & p orbitals, as they are the most important in organic chemistryS - orbitals are spherical with a nucleus at the centerP - orbitals are dumbbell shaped, with the nucleus in the middleD - orbitals are elongated dumbbell shaped (two dumbbells crossing on another), with the nucleus at the centerP-orbitals-there are three perpendicular p orbitals known as Px, Py and Pz, which lie on the corresponding axis, with the z axis (normally) coming out of the plane/page – there should normally be an axis diagram to show this-The lobes of the orbital are separated by a node, which doesn’t contain any electronsOrbitals further away from the nucleus have the most energyOrbitals are grouped into shells, which can be made up of different types of orbitals, with each orbital being able to be occupied by two electrons-The first shell contains one s orbital (1s) which can hold 2 electrons-The second shell contains one s orbital (2s) and three p orbitals (2p) – 8 electrons total-The third shell contains one s orbital (3s) three p orbitals (3p) and five d orbitals (3d)– 18 electrons totalV.Chemical BondsCarbon always has four bonds, and adopts a tetrahedron shape so that the bonds have sufficient spacing – the angles between the bonds are approximately 109 degreesAtoms form bonds because the compound that results is more stable than the separate atomsOrganic compounds have covalent bonds, because they share electrons and this makes them strongNoble gases don’t react with anything else because they have a full outer shell, the electrons do not want to separate and therefore the energy requirement is