2 How do we know what the filling order is? What chemistry tool might we rely on? (Stop)
3 Electron Configurations and the Periodic Table Valence electron configurations repeat down a group
4 Ground state electron configurations Example: Liatomic number = 3nucleus has 3 protonsneutral atom has 3 electrons2 electrons in 1s orbital, 1 electron in 2s orbital2s1s
5 Different ways to show electron configuration Energy level diagramBox notation2s1s2s1sSpectroscopic notationLi 1s2 2s1Read this “one s two” not “one s squared”Write the superscript 1. Don’t leave it blank
6 Using the Periodic Table The last subshell in the electron configuration is one of these(row #) s (row # – 1) d(row #) p (row # – 2) f
8 Electron configuration of O Atomic number of O = 8 so neutral atom has 8 e–
9 Electron configuration of Co Atomic number of Co = 27 so neutral atom has 27 e–
10 Simplifying electron configurations Shorthand Noble Gas Configuration Build on the atom’s noble gas coreHe 1s2O 1s22s22p4O [He]2s22p4Ar 1s22s22p63s23p6Co 1s22s22p63s23p64s23d7Co [Ar]4s23d71s2s2p1s2s2p3s3p4s3d
11 Noble Gases Far right of the periodic table These elements are extremely unreactive or inertThey rarely form compounds with other elements
12 Noble Gas electron configurations What is the electron configurations for NeonAbbreviated way to write configurationsStart with full outer shell then add onBrBa
13 Noble GasesNeon- emits brilliant light when stimulated by electricity – neon signs- 4th most abundant element in the universe.Helium- light non reactive gas- used balloons- inexpensive, plentiful and harmlessRadon- radioactive gas- can cause cancer- colorless, odorless emitted from for certain rocks underground
14 Why are we doing all of this? Properties of atoms correlate with the number and energy of electronsElectron configurations are used to summarize the distribution of electrons among the various orbitals
15 Electron configuration of ions What is an ion?How many electrons does Cl1- have?What is the electron configuration for the chloride ion?How many electrons does Ca2+ have?What is the electron configuration for the calcium ion?What do you notice?
16 Why is this important Valence electrons Electrons in the outermost energy levelWhere all the action occurs
18 Find the electron configuration of Au Locate Au on the periodic table
19 Find the electron configuration of Au Au [Xe]The noble gas core is Xe
20 Find the electron configuration of Au Au [Xe]6s2The noble gas core is XeFrom Xe, go 2 spaces across the s-block in the 6th row 6s2
21 Find the electron configuration of Au Au [Xe]6s24f14The noble gas core is XeFrom Xe, go 2 spaces across the s-block in the 6th row 6s2Then detour to go 14 spaces across the f-block 4f14note: for the f-block, n = row – 2 = 6 – 2 = 4
22 Find the electron configuration of Au Au [Xe]6s24f145d9The noble gas core is XeFrom Xe, go 2 spaces across the s-block in the 6th row 6s2Then detour to go 14 spaces across the f-block 4f14note: for the f-block, n = row – 2 = 6 – 2 = 4Finally go 9 spaces into the d-block on the 6th row 5d9note: for the d-block, n = row – 1 = 6 – 1 = 5
23 Practice Draw the orbital diagram for sulfur. What ion does sulfur want to form and why?Draw the orbital diagram for Potassium.
24 What does this meanProperties of atoms correlate with the number and energy of electronsAtoms like to have full outer shells.
27 Preview 4 Periodic Trends 2 main factors affect periodic trends Atomic Size/RadiusIonic Size (**)Ionization EnergyElectronegativity2 main factors affect periodic trendsNumber of electron shells (group)Effective Core Charge (ECC) (period)
28 Term (Refer to Definition Sheet) Effective Core Charge (ECC)1) The net charge that pulls on the valence electrons in an atom. The greater the effective core charge, the greater the pull. It is determined by subtracting the number of core electrons from the number of protons in the nucleusFor example: Magnesium (label ECC on P.T.)
29 TermElectron ShellPattern across the period?Pattern down the group?
30 Periodic Trends Atomic radius The distance from the center of an atoms nucleus to it’s outermost electronMeasure of atomic size
31 Periodic Trends Graph the first 20 elements Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?Atomic radius
33 Atomic Radius Group Trend Period Trend Increases from top to bottom More energy levels or quantum levels (or “shell”) as you go down a group – atomic radius increasesPeriod TrendIncreases from right to leftAll electrons in the same energy level. Increased # of protons holds them closer to nucleus.Decrease in Effective Core (Nuclear) Charge (ECC)Calculate ECC for elements in period 2
36 Periodic Trends Size of an atom when electrons are added or removed. Electrons removed atom becomes smaller.Electrons added atoms become largerWhy?Electron-Electron RepulsionIonic Size
37 Ionic Size Cations Anions Positively charged ions formed when an atom of a metal loses one ormore electronsCationsSmaller than the correspondingatomNegatively charged ions formedwhen nonmetallic atoms gain oneor more electronsAnionsLarger than the correspondingatom
38 Periodic Trends Graph the first 20 elements Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?Ionic Size (label P.T.)
40 Ionic Size Group Trend Period Trend Increases from top to bottom More energy levels as you go down a group – ionic size increasesPeriod TrendDecreases as atoms lose more electronsIncreases dramatically as atoms start gaining electrons, decreases as atoms gain fewer electrons.
41 Periodic Trends Ionization Energy Energy needed to remove one of the electrons on an atom’s outer shell.How strongly does an atom hold it’s outermost electron.
42 Periodic Trends Graph the first 20 elements Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?Ionization Energy
44 Ionization Energy Group Trends Period Trend Increases from bottom to top.The closer outer shell electrons are to the nucleus the harder they are to remove.Period TrendIncreases from left to right.The more electrons in the outer shell the harder it is to remove one.Increase in Effective Core Charge (ECC)
46 Periodic Trends Electronegativity Is a measure of the level of attraction (pull) an atom exerts on the electrons of another atom.Ability of an atom to attract electronsWhich elements want to gain electrons the most?
47 Periodic Trends Graph the first 20 elements Periodic Trends Graph the first 20 elements. What is the trend down a group? Across a Period?Electronegativity
50 Electronegativity Group Trend Period Trend Increases from bottom to topAs radius decreases, electrons are closer to the nucleus (decrease in number of electron shells)Period TrendIncreases from left to rightThe more electrons in the outer shell (up to 7) the more the atom wants to attract electronsException: Trend does not apply to Noble GasesIncrease in Effective Core Charge (ECC)
54 Practice Se and Br P, S, Se Cl, Cl1-, Br, Br1- Mg, Mg2+, Na, Na1+ Smallest atomLowest Ionization EnergyP, S, SeLargest atomHighest Ionization EnergyCl, Cl1-, Br, Br1-Largest ionic sizeMg, Mg2+, Na, Na1+Smallest ionic size
55 Atomic Properties Definitions For Quiz – Monday Effective Core Charge:It is the net charge that pulls on the valence electrons in an atom.The greater the effective core charge, the greater the pull.It is determined by subtracting the number of core electrons from the number of protons in the nucleusValence ElectronsAre found in the outermost, valence, electron shell (Bohr model) of the atomCore electronsoccupy all of the inner electron, core, shells
56 Atomic Properties Definitions Ionization Energy:Energy needed to remove an electron from an atom or molecule.The higher the effective core charge and lower the number of electrons shells, the greater the ionization energyAtomic sizeHow big (e.g., radius) an atom isAtomic radius is measured from the center of the nucleus to the valence electron shell.The higher the effective core charge and lower the number of electron shells, the smaller the atom.ElectronegativityMeasure of the level of attraction (pull) an atom exerts on the electrons of another atom.The higher the effective core charge and lower the number of electron shells, the greater the electronegativity
57 Homework Atomic Structure Worksheet 5-3 Worksheet Study for Definition Quiz on Monday
58 Periodic Table Objective: Students know how to use the periodic table to identify alkali metals, alkaline earth metals, transition metals, metals, semimetals (metalloids), nonmetals, halogens and noble gases.
59 The Periodic TableDmitri Mendeleev – credited for the first periodic table in 1869.He had put element names and a few of their properties on cards and then arranged them in various ways to help his students learn them more easily.Arranged them so elements in the same column have similar properties.
65 Alkali Metals All alkali metals have 1 valence electron They are very reactiveReactivity of these elements increases down the groupAlkali metals: ay?docid= #Potassium, K reacts with water and must be stored in kerosene
66 Alkaline Earth MetalsAll alkaline earth metals have 2 valence electronsAlkaline earth metals are less reactive than alkali metalsThe word “alkaline” means “basic”common bases include salts of the metalsCa(OH)2Mg(OH)2
67 Properties of MetalsMetals are good conductors of heat and electricityMetals are malleableMetals are ductileMetals have high tensile strengthMetals have luster
68 Transition MetalsCopper, Cu, is a relatively soft metal, and a very good electrical conductor.Mercury, Hg, is the only metal that exists as a liquid at room temperature
69 Properties of Metalloids They have properties of both metals and nonmetals.Metalloids are more brittle than metals, less brittle than most nonmetallic solidsMetalloids are semiconductors of electricitySome metalloids possess metallic luster
70 Silicon, Si – A Metalloid Silicon has metallic lusterSilicon is brittle like a nonmetalSilicon is a semiconductor of electricityOther metalloids include:Boron, BGermanium, GeArsenic, AsAntimony, SbTellurium, Te
71 Nonmetals Nonmetals are poor conductors of heat and electricity Nonmetals tend to be brittleMany nonmetals are gases at room temperatureCarbon, the graphite in “pencil lead” is a great example of a nonmetallic element.
72 Examples of NonmetalsMicrospheres of phosphorus, P, a reactive nonmetalSulfur, S, was once known as “brimstone”Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure
73 Halogens Halogens all have 7 valence electrons Halogens in their pure form are diatomic molecules (F2, Cl2, Br2, and I2)Chlorine is a yellow-green poisonous gas
74 Noble GasesNoble gases have 8 valence electrons (except helium, which has only 2)they are chemically unreactiveColorless, odorless and unreactive; they were among the last of the natural elements to be discovered
77 Electron Configurations and Periodic Trends Write the electron configuration and draw an orbital diagram for each elementOrder each group of elements or ions based on given data for each property requested on cardUse the orbital diagrams to explain the pattern. (does it agree with the “trend”)
78 Objectives Use the periodic table to write electron configurations Use the periodic table to obtain information about the properties of elements