Ions and Ionic Bonding

An ion is an atom, or group of atoms, that has a net positive or negative charge. cation – ion with a positive charge If a neutral atom loses one or more electrons it becomes a cation. anion – ion with a negative charge If a neutral atom gains one or more electrons it becomes an anion. Na 11 protons 11 electrons Na + 11 protons 10 electrons Cl 17 protons 17 electrons Cl - 17 protons 18 electrons 2.5

A monatomic ion contains only one atom A polyatomic ion contains more than one atom 2.5 Na +, Cl -, Ca 2+, O 2-, Al 3+, N 3- OH -, CN -, NH 4 +, NO 3 -

13 protons, 10 (13 – 3) electrons 34 protons, 36 (34 + 2) electrons Do You Understand Ions? 2.5 How many protons and electrons are in Al ? 3+3+ How many protons and electrons are in Se ?

2.5

Objectives  Review Valence Electrons, Lewis Dot Structures, and Noble Gas Configurations

Objectives  Discuss, compare, and contrast the different types of ions and ionic bonding  Convert atoms to ions  Explore metallic bonding  Discuss naming of compounds  Explore the geometry of ionic and metallic bonding  Discuss, compare, and contrast the different types of ions and ionic bonding  Convert atoms to ions  Explore metallic bonding  Discuss naming of compounds  Explore the geometry of ionic and metallic bonding

2.6

A molecular formula shows the exact number of atoms of each element in the smallest unit of a substance An empirical formula shows the simplest whole-number ratio of the atoms in a substance H2OH2O H2OH2O molecularempirical C 6 H 12 O 6 CH 2 O O3O3 O N2H4N2H4 NH 2 2.6

ionic compounds consist of a cation and an anion the formula is always the same as the empirical formula the sum of the charges on the cation and anion in each formula unit must equal zero The ionic compound NaCl 2.6

Ionic Bonding  No sharing of electrons  Atoms become ions and fulfill the octet rule  There is still an attraction (electrostatic forces) between the ions so they stay together in a specific arrangement – ionic bond  This arrangement has more to do with geometry than anything though  No sharing of electrons  Atoms become ions and fulfill the octet rule  There is still an attraction (electrostatic forces) between the ions so they stay together in a specific arrangement – ionic bond  This arrangement has more to do with geometry than anything though

Ionic Bonding  Typically, ionic bonding occurs when a cation and an anion exchange electron(s). This forms what is commonly called a salt.

What happens in ionic bonding

Polyatomic ions that you need to know (Quiz Next Week) NameFormulaNameFormula AmmoniumNH 4 + SulfateSO 4 2- HydroxideOH - PhosphatePO 4 3- CarbonateCO 3 2- ChlorateClO 3 - NitrateNO 3 - ChromateCrO 4 2- PermanganateMnO 4 - AcetateC2H3O2-C2H3O2-

Chemical Nomenclature  Ionic Compounds  often a metal + nonmetal  anion (nonmetal), add “ide” to element name  Ionic Compounds  often a metal + nonmetal  anion (nonmetal), add “ide” to element name BaCl 2 barium chloride K2OK2O potassium oxide Mg(OH) 2 magnesium hydroxide KNO 3 potassium nitrate 2.7

 Transition metal ionic compounds  indicate charge on metal with Roman numerals  Transition metal ionic compounds  indicate charge on metal with Roman numerals FeCl 2 2 Cl - -2 so Fe is +2 iron(II) chloride FeCl 3 3 Cl - -3 so Fe is +3 iron(III) chloride Cr 2 S 3 3 S so Cr is +3 (6/2) chromium(III) sulfide 2.7

Bellringer – Chemistry  Agenda  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes  Agenda  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes Clear Targets I can explain how ionic and metallic bonds are formed I can relate the physical properties of metals and alloys to their chemical make up. Polyatomic Ion Quiz Tomorrow Paper Due 15 th.

Ionic Bonding  Chemical Formula – shows the kinds and numbers of atoms in the smallest representative sample  Formula unit – the formula using the lowest whole number ratio of ions in an ionic compound  Chemical Formula – shows the kinds and numbers of atoms in the smallest representative sample  Formula unit – the formula using the lowest whole number ratio of ions in an ionic compound

Properties of Ionic Compounds  Most ionic compounds are crystalline solids at room temperature  Have high melting points  Can conduct electricity when melted or dissolved in water  Coordination number – the number of ions of the opposite charge that surround the ion in a crystal  Surrounded by 6 ions of the opposite charge – CN = 6  Most ionic compounds are crystalline solids at room temperature  Have high melting points  Can conduct electricity when melted or dissolved in water  Coordination number – the number of ions of the opposite charge that surround the ion in a crystal  Surrounded by 6 ions of the opposite charge – CN = 6

Bellringer – Chemistry  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes Clear Targets I can explain how ionic and metallic bonds are formed I can relate the physical properties of metals and alloys to their chemical make up. Polyatomic Ion Quiz Tomorrow Paper Due 15 th.

Metallic Bonding  Metallic Bonding Metallic Bonding  Metals are not made up of neutral atoms’  They are rather closely packed cations  The valence electrons of these metal atoms act  like a sea of electrons (they are mobile and can drift)  This explains conductivity (electrons flow)  It also explains ductility and malleability ( the positive ions can flow around. In a non metal they cannot move away from each other, so when the positive ions are in each other’s presence the compound shatters)  Metallic Bonds consist of these electrons being attracted to the positive metallic ions  Metallic Bonding Metallic Bonding  Metals are not made up of neutral atoms’  They are rather closely packed cations  The valence electrons of these metal atoms act  like a sea of electrons (they are mobile and can drift)  This explains conductivity (electrons flow)  It also explains ductility and malleability ( the positive ions can flow around. In a non metal they cannot move away from each other, so when the positive ions are in each other’s presence the compound shatters)  Metallic Bonds consist of these electrons being attracted to the positive metallic ions

Bellringer – Chemistry  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes Clear Targets I can explain how ionic and metallic bonds are formed I can relate the physical properties of metals and alloys to their chemical make up. Polyatomic Ion Quiz Tomorrow Paper Due 15 th.

Crystalline Structure of Metals  Most metals are arranged in very compact and orderly patterns.  Body Centered Cubic – every atom has eight neighbors  Face Centered Cubic – every atom has 12 neighbors  Hexagonal Close Packed - every atom has 12 neighbors (but in a different way)  Most metals are arranged in very compact and orderly patterns.  Body Centered Cubic – every atom has eight neighbors  Face Centered Cubic – every atom has 12 neighbors  Hexagonal Close Packed - every atom has 12 neighbors (but in a different way)

Bellringer – Chemistry  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes Clear Targets I can explain how ionic and metallic bonds are formed I can relate the physical properties of metals and alloys to their chemical make up. Polyatomic Ion Quiz Tomorrow Paper Due 15 th.

Alloys  Alloys – mixture of elements where at least one is a metal  This is done because often the properties of the alloys are superior to the metal itself  Substitutional Alloy – an alloy where one of the parts of the crystalline structure is replaced by another element (happens when the atoms are of similar sizes)  Interstitial Alloy – an alloy where the atoms are of different sizes and the new atom fits into the spaces (interstices) between the larger atoms.  Alloys – mixture of elements where at least one is a metal  This is done because often the properties of the alloys are superior to the metal itself  Substitutional Alloy – an alloy where one of the parts of the crystalline structure is replaced by another element (happens when the atoms are of similar sizes)  Interstitial Alloy – an alloy where the atoms are of different sizes and the new atom fits into the spaces (interstices) between the larger atoms.

Bellringer – Chemistry  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes  Agenda  Bellringer (5min)  Notes on Ionic Bonds  Questions  Notes on Metallic Bonds + properties  Begin Metallic Bonding  Lab tomorrow if finished with notes Clear Targets I can explain how ionic and metallic bonds are formed I can relate the physical properties of metals and alloys to their chemical make up. Polyatomic Ion Quiz Tomorrow Paper Due 15 th.