Electron Configuration Orbital Notation Electron Configuration Notation Noble gas Notation Follow along starting on p.111 in your textbook

What is electron configuration? It is simply the arrangement of electrons in an atom. There are 3 basic rules, or principles, that determine how electrons will be arranged: – the Aufbau principle (this will lead to some d-block exceptions later) – the Pauli exclusion principle – Hund’s rule *Find each definition in your textbook and write it down. We will briefly discuss each after they are written.

What does it all mean? Electrons are arranged in main energy levels, sublevels and orbitals. – The main energy levels are numbered 1 through 7. – The sublevels can be s, p, d, or f – Each sublevel will have an odd number of orbitals that can hold 2 electrons each. S has 1 orbital = _______ electrons P has 3 orbitals = _______ electrons D has 5 orbitals = _______ electrons F has 7 orbitals = _______ electrons

Electron Configuration Notation This notation contains only numbers, letters, and exponents to represent the number of electrons in each sublevel. Each electron configuration notation will start with a Hydrogen configuration (1s 1 ) and continue in order following the periodic table (or figure 16 on p.111, or figure 19 on p.116)

Examples Hydrogen Helium Lithium Boron Nitrogen Neon Silicon Calcium

Orbital Notation The simplest way to notate an element’s electron configuration is with each orbital represented and each electron drawn. Each arrow represents one electron. Orbitals will fill with an up arrow first, then a down arrow. – Multiple orbitals will each fill with an up arrow before being completed with a down arrow.

LOTS of examples Hydrogen Helium Lithium Boron Nitrogen Neon Silicon Calcium

Noble Gas Notation This is the most common notation to find and the easiest to write. Begin with the noble gas just before the element that you are notating, then fill in the electron configuration from there.

Examples Hydrogen Helium Lithium Boron Nitrogen Neon Silicon Calcium

d block elements The d block contains the transition metals from periods 4 through 7. Normally, you would write the period number before your block letter. However, when numbering the d block, subtract 1 from the period number. So, the d block in the 4 th period would be called 3d.

3d Examples *3d is always written before 4s Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc

4d examples *4d is always written before 5s YttriumZirconium NiobiumMolybdenum TechnetiumRuthenium RhodiumPalladium SilverCadmium

The f block The f block is unique for the following reasons: – It makes the 6 th and 7 th periods much longer because they are meant to be inserted right after Ba for the Lanthanides and after Ra for the Actinides. – When notating the f block, subtract 2 from the normal period number (ex. Period 6 would be 4f). – Technically, Lanthanum (La) and Actinium (Ac) are in the d block (see the spaces?), so the Lanthanide notations will be 4f __ 5d 1 6s 2. Actinides will each be one number higher. You will not be required to complete any f-block electron configurations, but you must be able to explain how it is different from the s, p, and d blocks.

Examples You will not be required to complete any f- block electron configurations, but you must be able to explain how it is different from the s, p, and d blocks.

Practice on your own Complete the practice problems on pages 113, 121, and p.122 You will only need to create orbital notations for elements in periods 1-4. You will be required to be able to complete an electron configuration notation and a noble gas notation for every element on the periodic table through Barium.

Exceptions There are always exceptions to any rule (remember the Aufbau principle?), and some elements do not follow the order exactly as it is set in figure 19. You must MEMORIZE the exceptions from the fourth and fifth periods: TABLE 5 p.118 TABLE 6 p.120

Assignment Complete the 4.3 section review on p.122 – (due by the end of class today) Your chapter review assignment will be due by the end of class Monday: – Chapter 4: P.124 – 126 (#4-9, 15, 23-32, 35-41, 46) 25 problems – Chapter 5: p.166 – 169 (#1-4, 7-9, 11, 13-17, 22-25, 27-32, 35, 37, even) 29 problems **This is a lot of problems! Don’t wait until Monday to start or you will not finish!!