Unit 3 Valence Electrons and Ions. Subatomic Particles In an atom Protons and neutrons are clumped...
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Transcript of Unit 3 Valence Electrons and Ions. Subatomic Particles In an atom Protons and neutrons are clumped...
Subatomic ParticlesSubatomic Particles
In an atom Protons and neutrons are In an atom Protons and neutrons are clumped together in a very small clumped together in a very small dense nucleusdense nucleus
The Electrons are found outside of The Electrons are found outside of the nucleus in various electron cloudsthe nucleus in various electron clouds
Principle Energy LevelsPrinciple Energy Levels
The electron clouds are found at The electron clouds are found at specific distances from the nucleus specific distances from the nucleus called called Principle Energy LevelsPrinciple Energy Levels
Lowest energy levels are closest to the Lowest energy levels are closest to the nucleusnucleus
Highest energy levels are farthest Highest energy levels are farthest from the nucleusfrom the nucleus
Fill from Lower Fill from Lower Higher energy levels Higher energy levels
Energy Level ‘Clouds’Energy Level ‘Clouds’
phycomp.technion.ac.il/~phr76ja/lecture1.html hoku.as.utexas.edu/.../a309f04/lect1cos.html
BohrBohr
The Bohr model is used to show The Bohr model is used to show electron placements in the energy electron placements in the energy levels.levels.
Elements in the same row of the Elements in the same row of the periodic table have the same number periodic table have the same number of occupied energy levelsof occupied energy levels
Energy LevelsEnergy Levels
First energy level- max First energy level- max 2 electrons2 electrons
Second energy level- max Second energy level- max 8 electrons8 electrons
Third energy level- max Third energy level- max 8 electrons8 electrons
Fourth energy level- max Fourth energy level- max 18 electrons18 electrons
Valence ElectronsValence Electrons
The electrons that occupy the The electrons that occupy the highest energy level (or the outer highest energy level (or the outer shell) are called shell) are called Valence ElectronsValence Electrons
Valence electrons are important Valence electrons are important because they are the electrons because they are the electrons involved in chemical reactionsinvolved in chemical reactions
This means that the number of This means that the number of valence electrons determines an valence electrons determines an element’s chemical propertieselement’s chemical properties
Valence ElectronsValence Electrons
Elements in the same column of the Elements in the same column of the Periodic Table have the same Periodic Table have the same number of valence electrons and number of valence electrons and have similar chemical properties.have similar chemical properties.
IonsIons
When elements undergo chemical When elements undergo chemical reactions they either share or reactions they either share or exchange electrons with other exchange electrons with other elements to fill their outer shells.elements to fill their outer shells.
Atoms that have either lost or gained Atoms that have either lost or gained electrons are called ions.electrons are called ions.
Unlike neutral atoms, ions have a net Unlike neutral atoms, ions have a net charge.charge.
Ion ChargesIon Charges
The number of electrons that it has lost or The number of electrons that it has lost or gained determines an ion’s chargegained determines an ion’s charge
Ions that Ions that GAINGAIN electrons have a electrons have a NEGATIVENEGATIVE charge and are called charge and are called anionsanions..
Ions that Ions that LOSELOSE electrons have a electrons have a POSITIVEPOSITIVE Charge and are called Charge and are called cations.cations.
Lithium FluorideLithium Fluoride
F + 1 e- F + 1 e- F F-1-1
Li Li Li Li+1+1 + 1 e- + 1 e-
Li + F Li + F LiF LiF
HClHCl
Draw Bohr Models for Hydrogen and Draw Bohr Models for Hydrogen and Chlorine and then show how they Chlorine and then show how they combine.combine.
Cl + 1 e- Cl + 1 e- Cl Cl-1-1
H H H H+1+1 + 1 e- + 1 e-
H + Cl H + Cl HCl HCl
Ion DrawingsIon Drawings
Draw Bohr models for the following Draw Bohr models for the following elements:elements:– OxygenOxygen– Sodium Sodium – MagnesiumMagnesium– BromineBromine
Ion DrawingsIon Drawings
In your lab groups draw Bohr models In your lab groups draw Bohr models for the following elements:for the following elements:– Oxygen (2)Oxygen (2)– Hydrogen (2)Hydrogen (2)– Sodium (1)Sodium (1)– Chlorine (1)Chlorine (1)– Magnesium (1)Magnesium (1)– Calcium (1)Calcium (1)– Bromine (2)Bromine (2)
Combine IonsCombine Ions
Cut out the circles and combine the Cut out the circles and combine the Ions to make the following Ions to make the following compounds. Draw arrows to show the compounds. Draw arrows to show the movement of the electronsmovement of the electrons– HH22O O WaterWater
– NaClNaCl Sodium ChlorideSodium Chloride
– CaBrCaBr22 Calcium BromideCalcium Bromide
– MgOMgO Magnesium OxideMagnesium Oxide