CH 101 1st Edition Lecture 6 Outline of Last Lecture I Light waves A How to Calculate the Wavelength and the Frequency II The Bohr Model A Absorbing energy B Emitting energy III Recap of Important Equations Outline of Current Lecture I The Schrodinger Model of the Atom A Nodes II Introduction to Quantum Numbers III The Pattern Within Energy Levels IV What Orbitals Look Like B Electron Configuration V Quantum Numbers on the Periodic Table Current Lecture I The Schrodinger Model of the Atom When it was discovered that electrons don t always act as particles but can act as waves the Bohr model of the atom had to be revised The revised model is called the Schrodinger model it shows the electrons in an atom moving in wave patterns The wavelength of a wave can be determined if you know the energy level of the electron the equation is 2L n where L is the length in centimeters A Nodes Nodes are the points of the wave that seem to stay in place If you are just given the energy level n The amount of nodes in that energy level can be determined by n 1 amount of nodes Therefore the first energy level has zero nodes the second energy level as one node and so on II Introduction to Quantum Numbers Schrodinger came up with quantum numbers to represent where the electron is within the atom These 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 Principal Quantum Number n Tells you the energy level or shell the electron is on This is similar to the Bohr model because the larger the n value is the farther away from the electron is from the nucleus Orbital Quantum Number l Is a sublevel of the energy levels and determines the amount of nodes the value of l can never be the same or more than the value of n The values of l are represented with letters 0 s 1 p 2 d 3 f 4 g and 5 h For example within the n 2 energy level there are two sub levels 2s and 2p the third energy level has three sublevels 3s 3p and 3d Magnetic Orbital Quantum Number ml This number determines the orientation of the sublevel because it is the amount of orbitals a sublevel can have The value of ml Is determined by taking the amount for l and subtracting it from 0 Then you count the number of orbitals within the range l of and l For example the sublevel p equals 1 node to determine the you write out 1 0 1 and determine that the sublevel p has ml 3 Spin Quantum Number ms The spin quantum number can only equal or This tells you the direction of the electrons spin around the nucleus III The Pattern Within Energy Levels Just because the n is larger doesn t mean the electron has more energy The ranking of energy is determined by n l and if two answers come out the same the electron with the larger n is higher in energy This means that an electron at 3d has more energy than an electron at 4s Ex An electron at which orbital would have the most energy 4d or 5s Start by determining what n and l equal n equals the coefficient and equals the letter which corresponds to a number 0 s 1 p 2 d 3 f 4 g and 5 h Then plug it into the equation n l 4d n 4 l 2 4 2 6 This is the higher number therefore 4d has more energy than 5s 5s n 5 l 0 5 0 5 IV What Orbitals Look Like The shape of the orbital is determined by the n the l and the ml The l determines the shape the ml determines how many orbitals there are an orbitals means the path the electron travels within the subshell and the n determines how big the orbital is the larger the n the larger the orbital The exact orientation of each orbital is not as important as knowing the general shape of it Here is a simple chart to help you understand how the amount of nodes and orbitals affect the shape The l the amount of nodes The ml The amount of orbitals s 0 nodes 0 only 1 orbital General shape of the orbital p 1 node 1 0 1 3 orbitals d 2 nodes 2 1 0 1 2 5 orbitals f 3 nodes 3 2 1 0 1 2 3 7 orbitals A Electron Configuration Electron configurations are created out of quantum numbers The l letters s p d f etc tell you the maximum amount of electrons that can be in that orbital by multiplying the number of orbitals ml by two because the orbital is formed when two electron are attracted to each other The amount of electrons in an atom are represented by an electron configuration Here is what an electron configuration chart looks like each blank square can hold two electron facing opposite directions one electron must always be pointing up and the other pointing down If there are not enough electrons to fill a row of boxes distribute the electrons so that every box in that row gets an electron there cannot be a box with two electrons in it in the same row as a blank box the electron would need to be dispersed to fill the blank box Neon s electron configuration is 1s2 2s2 2p6 showing that neon has 10 electrons When you draw out the electron configuration of neon it looks like this Oxygen s electron configuration is 1s2 2s2 2p4 because oxygen only has 8 electrons Its electron configuration chart would look like this Excited State An electron is in an excited state when there electron configuration has an odd number or if a level isn t filled and an electron is on the next level Here are examples of excited states Grounded State A ground state is when an electron configuration has no unpaired electrons and if it does has unpaired electron they fill up the whole orbital level These are examples of ground states V Quantum Numbers on the Periodic Table Quantum numbers are easy to find on the periodic table because they are grouped together The only thing you have to remember is that helium moves to the s block Using the periodic table to find the electron configuration of an element is tedious but with practice you will start to understand how the table works First locate the element and see what row it is in Next start with the s block and see how many rows you have to go through till you get to the element if you start at hydrogen in the top left corner and move from left to right across the table The number of rows you go through in that block will be your n value Then do this for each block you go through …