Presentation on theme: "Ionic Compounds and Metals"— Presentation transcript:
1 Ionic Compounds and Metals Bonding and PropertiesChapter 7- pages
2 Ions & Ionic Bonding Section 7.1: Ion Formation; pg 206-209 Learning Goals:I understand how positive ions (cations) and negative ions (anions) are formed.I understand why ions form and can relate ion formation to the valence electrons of an element.Understanding the above is crucial to understanding chemistry- how elements combine to form compounds and chemical reactions.
3 Ion Formation Review What is the octet rule? Why do elements form ions?Which electrons are involved when ions are formed?What are positive ions called?What are negative ions called?
4 Ion FormationAll elements are trying to become like a noble gas, in other words become more stable.Elements achieve this stability by losing or gaining electrons to reach a full octet of valence electrons.Some exceptions to the octet rule are:Elements 1-5: H, He, Li, Be and B.Transition metals
6 Ion Formation Lewis Dot Structures: a simple shorthand way to represent valence electrons.Used as an alternative to electron configurations and drawing atomic models.Example: •Na → NaOther ways to show ion formation: electron configurations & orbital diagrams.
8 Ion Formation A cation is a positively charged ion. Formed when a neutral element loses electrons.All group #1 (alkaline metals), group #2 (alkaline earth metals) and group #13 (boron group) form cations.An anion is a negatively charged ion.Formed when a neutral element gains electrons.All group #15 (nitrogen group), group #16 (oxygen group) and group #17 (halogen group) form anions.Because it has 4 valence electrons, the carbon group can form both cations and anions, although we generally consider them to have a charge of zero.
9 Ionic Bonds and Ionic Compounds Section 7.2, pages
10 Ionic Bonding Learning goals: Ionic bonds are formed when electrons are transferred from one atom to another.Ionic bonds are held together by electrostatic attraction.
11 Ionic Bonding Chemical Bond- is the force that holds 2 atoms together. There are 3 general types of bondingIonic: ex. NaCl, CaCl2, FeSMetallic: ex. copper, iron, brassCovalent: ex. CH4, C6H12O6
12 Ionic Bonding: The Formation of Sodium Chloride Sodium has 1 valence electronChlorine has 7 valence electronsAn electron transferred giveseach an octetNa 1s22s22p63s1Cl 1s22s22p63s23p5
13 Ionic Bonding: The Formation of Sodium Chloride This transfer forms ions, each with an octet:Na+ 1s22s22p6Cl- 1s22s22p6 3s23p6
14 Ionic BondingIonic bonds are held together by electrostatic attraction. This is the force of attraction by opposite charges.The atom is held together by the electrostatic attraction of electrons(e-) and protons (p+).Ionic compounds are held together by the electrostatic attraction of the cation (+) and anion (-).
15 Ionic BondingIn general metals form cations and nonmetals form anions.The oxidation state is the charge on a given ion.Na+ oxidation state = +1Ca+2 oxidation state = +2Cl- oxidation state = -1Some metals can form ions with multiple oxidation states.Fe+2, Fe+3Cu+, Cu+2
16 Naming Ionic Compounds A cation retains the name from the element it was formed from.Na+ sodium cationCa+2 Calcium cationAl+3 aluminum cationAn anion is named by adding the suffix -IDE at the end of the name of the element it was formed from.Cl- chloride anionS-2 sulfide anionO-2 oxide anionN-3 nitride anion
17 Naming Ionic Compounds Ionic compounds are named by combining the names of the cations and the anions.NaCl sodium chlorideNaF sodium fluorideCaCl2 calcium chlorideMgO magnesium oxideFeS iron sulfide
18 Ionic Compounds Properties The packing of these positively charged cations and negatively charged anions must balance the forces of attraction and repulsion between the atoms.
19 Ionic Compounds Properties The repeating patternof particle packing in anionic compound is calledan ionic crystal.
20 Ionic Compounds Properties A crystal lattice is the three-dimensional geometric arrangement of particles, and is responsible for the structure of many minerals.Quartz, SiO2Pyrite, FeS2
21 Ionic Compounds Properties In a solid, ions are locked into position and electrons cannot flow freely—solid ions are poor conductors of electricity.Liquid ions or ions in aqueous solution have electrons that are free to move, so they conduct electricity easily.An ion in aqueous solution that conducts electricity is an electrolyte.
22 Physical Properties of Ionic Compounds The properties of ionic compounds can be explained by the strong attractive forces between the cations and anions-electrostatic attraction.Ionic compounds have very high melting and boiling points compared to most other solid compounds.Ionic bonds are very strong compared to metallic and covalent bonds.
23 Physical Properties of Ionic Compounds Ionic compounds are hard, rigid and brittle
24 Ionic BondingPositive and negative ions exist in a ratio determined by the number of electrons transferred from the metal atom to the non-metal atom.Example:NaClCaCl2
25 Names and Formulas for Ionic Compounds Sodium + ChlorineSodium + OxygenPotassium + IodineCalcium + OxygenCalcium + Bromine
29 AssessmentExplain how an ionic compound made up of charged particles can be electrically neutral.Name 3 properties of ionic compounds.Why are ionic compounds so strong?4. How would you write the following ionic compounds:Potassium and fluorideMagnesium and chlorideSodium and oxygen
30 Review on Ionic Bonding Which elements/groups form cations? Why?Which elements/groups form anions? Why?
31 Metals & Metallic Bonding Section 7.4- pagesLearning Goals:I can describe a metallic bond and I understand how a metallic bond differs from an ionic bond.I understand the physical properties of metals and can relate these properties to their valence electrons.I can define and describe what alloys are.
32 Metallic BondingMetals form crystal lattices in the solid state and can be modeled as cations surrounded by a “sea”of freely moving valence electrons.A metallic bond is the attraction of a metallic cation for these delocalized electrons.
33 Metallic BondingThe metal ions are tightly packed in the crystal and their “d” electron orbitals overlap.The electron sea model proposes that all metal atoms in a metallic solid contribute their valence electrons to form a "sea" of electrons.The electrons are free to move around and are referred to as delocalized electrons.
34 Review from last week What are the 3 types of bonds? Why do ions form? What interaction holds ionic bonds together?Last week’s BIG IDEA: oppositely charged ___________ attract each other, forming electrically _________ ___________ ____________.What ion does Ca form? What is its oxidation state?