Valence Electrons

Valence Electrons Day 1ReviewElectrons are the negatively charged part of the atomElectrons are found in orbitals around the nucleusWe write the electron configuration of the element to see the different orbitals the electrons are located inReviewWrite the electron configuration for Lithium

Write the electron configuration for FluorineValence electronsThe electrons in the last energy level of the element are the VALENCE electronsThe last energy level is the part of the configuration that has the largest number in front of it

Lithium = 1s2 2s1 Fluorine = 1s2 2s22p5

Valence electronsAn element can have anywhere from 1-8 valence electronsThe number of valence electrons determines how REACTIVE the element is8 = totally unreactive1 and 7 = extremely reactive2 and 6 = pretty reactive3-5 = only kinda reactive

How to find valence electrons?Pull out your periodic table!

You can find the valence electron of the element by seeing what group it is in.

Where are the groups on the periodic table?You should already have groups 1-18 listed on your periodic table

Group 1 = 1 Valence ElectronGroup 2 = 2 Valence ElectronsGroup 13 = 3 Valence ElectronsGroup 14 = 4 Valence ElectronsGroup 15 = 5 Valence ElectronsGroup 16 = 6 Valence ElectronsGroup 17 = 7 Valence ElectronsGroup 18 = 8 Valence ElectronsWhat about groups 3-12?The transition metals in groups 3-12 have their own set of rules

Dont worry about them for nowIn - Class Practice: Due at end of hour!Write down the following elements on a sheet of paper next to them find out how many valence electrons they have?

1. Neon2. Sodium 3. Aluminum4. Calcium 5. Sulfur 6. Iodine 7. Carbon8. Lead 9. Phosphorus 10. Krypton

Valence Electrons Day 2ReviewHow many valence electrons does Arsenic have?

How many valence electrons does Potassium have?Valence Electrons To find the number of valence electrons for the elements in groups 1,2 and 13-18 you look at your periodic table

Transition metals (groups 3-12) have their own rulesTransition MetalsTo find the number of valence electrons for a transition metal you have to write the shorthand electron configuration for that metal

For example Irons shorthand electron configuration is [Ar] 4s2 3d6Transition MetalsJust like the regular valence electrons, we look at the highest energy level

Irons shorthand electron configuration is [Ar] 4s2 3d6 4s2 = highest energy level

Iron has 2 valence electronsTransition Metals All transition metals will have a shorthand configuration that gives you 2 valence electrons

However, Transition Metals can act like they have anywhere from 1-4 electrons

HomeworkValence Electrons side of worksheet

For each question you shouldWrite the shorthand electron configurationWrite how many valence electrons each element hasValence Electrons Day 3ReviewBy now we know that an element can have anywhere from 1-8 valence electrons

We can find the number of valence electrons the element has by looking at the periodic table or by its electron configurationValence Electron ReviewFor Groups 1,2, 13-18 the number of valence electrons depends on group it is inException! Helium is a noble gas and is full, but because of its electron configuration it has 2 valence electrons, not 8Transition metals in groups 3-12 all have 2 valence electrons, even though they dont always act that wayLewis StructuresWe can draw Lewis Structures to represent the valence electrons of an element

To draw a Lewis StructurePut the element symbol in the middleDetermine how many valence electrons it hasDraw a dot for each electron around the symbol

Important Rules As you are putting the dots around the symbol you start by putting one dot on each side of the symbolNo side should ever have more than 2 dotsExample: Electron dot diagram for Carbon

: C: C PracticeDraw the electron dot diagramPut the element symbol in the middleDetermine how many valence electrons it hasDraw a dot for each electron around the symbol

NaClMgArHomeworkLewis Dot Diagrams side of worksheet

Remember, Helium is an exception to the noble gases, it only has 2 valence electrons!