Introduction to Matter

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Introduction to Matter

Lesson 4Hand in homeworkMoles, Formulae and Equations workbook.Use spdf notation to write the electronic configuration for the first 20 elements

Assessment Criteria1.1 Define an element giving examples.1.2 Write the names and symbols of the first 20 elements.1.3 Describe and explain what some of the general physical properties of metals and non-metals are1.4 Describe the relative position of metals, non-metals, groups and periods within the periodic table with examples.2.1 Classify substances as elements or compounds from their names giving examples2.2 Describe two differences between a compound and a mixture3.1 Describe protons, neutrons and electrons in terms of their relative charges and relative masses.3.2 Describe the distribution of mass and charge within an atom.3.3 Describe the contribution of protons and neutrons to atomic nuclei in terms of atomic number and mass number.3.4 Deduce the electronic configurations of atoms up to z = 36 and ions, given the atomic number and charge, limited to s and p blocks up to Z= 36.4.1 Describe ionic bonding as the electrostatic attraction between two oppositely charged ions including dot and cross diagrams.4.2 Describe a covalent bond as a pair of electrons shared between two atoms4.3 Write the formulae for some simple and some complex compounds4.4 Describe and interpret and/or predict physical properties in terms of the types motion and arrangement of particles (atoms, molecules and ions) and the forces between them, and the different types of bonding.5.1 Describe an acid as a species that can donate a proton.5.2 Describe a base as a species that can accept a proton5.3 Describe the reaction of an acid typified by hydrochloric acid with metals, carbonates bases and alkalis and interpret them using ionic equations to emphasise the role of H+(aq)5.4 Write a balanced equation for the reaction between two elements and between an acid and a base6.1 Construct balanced chemical equations, full and ionic

Review ActivityExplain how the following rules effect electron configuration.Aufbau principlePauli Exclusion PrincipleHunds Rule

Review Activity Draw an Aufbau diagram for the following elements.

LithiumSodiumPotassium

6Review Activity Draw a diagram to show how the diagonal rule affects the electron orbital filling order.

Todays AimRecognise that chemical reactions involve outer shell electrons to produce ionic and covalent compounds and appreciate the significance of noble gas electron arrangementWeek 4. 4.1 Describe ionic bonding as the electrostatic attraction between two oppositely charged ions including dot and cross diagrams.4.2 Describe a covalent bond as a pair of electrons shared between two atoms4.3 Write the formulae for some simple and some complex compounds4.4 Describe and interpret and/or predict physical properties in terms of the types motion and arrangement of particles (atoms, molecules and ions) and the forces between them, and the different types of bonding.

Week 4 ReadingAccess to ChemistryAlan Jones, Mike Clement, Avril Higton Elaine GouldingISBN 0 -85404-564-3

Atoms and IonsPages 55 - 73

4.1 Describe ionic bonding as the electrostatic attraction between two oppositely charged ions including dot and cross diagrams.

Ionic BondingAn ionic bond is a chemical link between two atoms caused by the electrostatic force between oppositely-charged ions in an ionic compound.

Are made up of:a metal ion and a nonmetal ion.A metal ion and polyatomic ions.

Exception to this rule is hydrogen fluoride. This is determined by the significant difference in electronegativity between hydrogen and fluorine.

Ionic Bonds

Valence ElectronsWe have already encountered valence electrons on page 11 of the moles and formulae workbook.

Valence electrons are the electrons in the highest occupied energy level of the atom.

Valence electrons are the only electrons generally involved in bond formation. Electron Configuration of Sodium1s2 2s2 2p6 3s1

Which is the valence electron for Na?

Answer: 1s2 2s2 2p6 3s1

Na , 11 e

Na + , 10eA Positive Ion (Cation):An atom that has less electrons than protons due to the loss of one or more electrons from the stable atom state.Therefore the ion contains a positive charge18Electron Dot Structure or Lewis Dot Diagram A notation showing the valence electrons surrounding the atomic symbol.

Elements within the same group have the same electron-dot structure.20A Negative Ion (Anion)An atom that has more electrons than protons due to the gain of one or more electrons from the stable atom state.Therefore the ion contains a negative charge

21Chlorine Atom Chlorine Ion

When Na, (Z= 11) loses its valence electron, what element does its configuration look like ?NeonPotassium BerylliumSodium23C. discover the property called inertia.

When the valence shell is full, the atom is stable, less likely to react.

Example: Noble (Inert Gases)KrA Stable Octet 24NoteAtoms tend to react in a way that would lead them to have a stable octet.Equations for the Formation of CationsH. H+ + e-

Li. Li+ + e-

Mg: Mg2+ + 2e-

Equations for the Formation of Anions . .. : F : + e- : F - : .. .. Ionic CompoundsRemember from the definition

Are made up of:a metal and a nonmetal ion.A metal and polyatomic ions. Exception to this rule is hydrogen fluoride. This is determined by the significant difference in electronegativity between hydrogen and fluorine.

Example:Which of the following compounds are ionic?

NaClCO2COKFKNO3

BondingElements that do not have a complete octet, tend to react. When the elements react bonds are formed.

Types of BondsIonicMetallicCovalentIonic BondsBonds that are formed by transfer of electrons from one element to the other.

Each element (now an ion) will have a complete octet after the transfer of electrons.The Ionic BondThe electrical force of attraction between oppositely charged ions.

Na+F33Example: Formation of Lithium Fluoride . ..Li. + : F : Li+ : F - : .. .. Is an Ionic Compound Electrically Neutral or Charged?Movie Cliphttp://www.youtube.com/watch?v=Kj3o0XvhVqQ&NR=1

Chemical FormulaA representation of the kinds and number of atoms in a substance.Formula UnitA chemical formula that shows the lowest whole number ratio of the atoms (ions) in an ionic compound.

Example: KCl, Mg Cl2The formula unit is used because ionic compounds have a lattice arrangement of ions. Ex: NaClWhich ball represents the Na?

Ionic bonding workbookCovalentBondsIn an IONIC bond,electrons are lost or gained,resulting in the formation of IONSin ionic compounds.FKFKFKFKFKFKFKFK+_FK+_The compound potassium fluorideconsists of potassium (K+) ionsand fluoride (F-) ionsFK+_The ionic bond is the attractionbetween the positive K+ ionand the negative F- ion

4.2 Describe a covalent bond as a pair of electrons shared between two atoms

Covalent bonding is a chemical link that occurs when two non-metallic atoms in a molecule share electrons so that both of the atoms fill their outer shells. These electrons are shared in one or more pairs called electron pairs; each pair is a covalent bond. Atoms of different elements can bond covalently if they share similar electronegativities. When atoms share one, two, or three pairs of electrons, they are considered to have a single, double, or triple bond, respectively.In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule). In covalent bonding,atoms still want to achievea noble gas configuration(the octet rule). But rather than losing or gainingelectrons,atoms now share an electron pair.But rather than losing or gainingelectrons,atoms now share an electron pair.The shared electron pairis called a bonding pairCl2ChlorineformsacovalentbondwithitselfClClHowwilltwochlorineatomsreact?ClClEach chlorine atom wants to gain one electron to achieve an octetClClNeither atom will give up an electron chlorine is highly electronegative.Whats the solution what can theydo to achieve an octet?ClClClClClClClClClCloctetClClcircle the electrons foreach atom that completestheir octetsoctetClClcircle the electrons foreach atom that completestheir octetsThe octet is achieved byeach atom sharing theelectron pair in the middleClClcircle the electrons foreach atom that completestheir octetsThe octet is achieved byeach atom sharing theelectron pair in the middleClClcircle the electrons foreach atom that completestheir octetsThis is the bonding pairClClcircle the electrons foreach atom that completestheir octetsIt is a single bonding pairClClcircle the electrons foreach atom that completestheir octetsIt is called a SINGLE BONDClClcircle the electrons foreach atom that completestheir octetsSingle bonds are abbreviatedwith a dashClClcircle the electrons foreach atom that completestheir octetsThis is the chlorine molecule,Cl2O2Oxygen is also one of the diatomic moleculesHow will two oxygen atoms bond?OOOOEach atom has two unpaired electronsOOOOOOOOOOOOOxygen atoms are highly electronegative.So both atoms want to gain two electrons.OOOxygen atoms are highly electronegative.So both atoms want to gain two electrons.OOOOOOOOOOOOBoth electron pairs are shared.6 valence electronsplus 2 shared electrons= full octetOO6 valence electronsplus 2 shared electrons= full octetOOtwo bonding pairs,OOmaking a double bondOO=For convenience, the double bond can be shown as two dashes. OOOO=This is the oxygen molecule,O24.3 Write the formulae for some simple and some complex compoundsMoles and formulae workbook exercise 2

Calcium ChlorideAluminium OxideMagnesium Hydroxide4.4 Describe and interpret and/or predict physical properties in terms of the types motion and arrangement of particles (atoms, molecules and ions) and the forces between them, and the different types of bonding.

Ionic Compounds

Crystalline solids (made of ions) High melting and boiling points Conduct electricity when melted Many soluble in water but not in nonpolar liquid

Covalent Compounds

Gases, liquids, or solids (made of molecules) Low melting and boiling points Poor electrical conductors in all phases Many soluble in nonpolar liquids but not in water

Review Week 44.1 Describe ionic bonding as the electrostatic attraction between two oppositely charged ions including dot and cross diagrams.4.2 Describe a covalent bond as a pair of electrons shared between two atoms4.3 Write the formulae for some simple and some complex compounds4.4 Describe and interpret and/or predict physical properties in terms of the types motion and arrangement of particles (atoms, molecules and ions) and the forces between them, and the different types of bonding.

HomeworkComplete section 6a pages 65 67Explain the difference in physical properties between Aluminium chloride and silicon tetrachloride.Melting pointBoiling pointDensitySolubilityElectrical Conductivity97Next Week Access to Chemistry pages 51 - 735.1 Describe an acid as a species that can donate a proton.5.2 Describe a base as a species that can accept a proton5.3 Describe the reaction of an acid typified by hydrochloric acid with metals, carbonates bases and alkalis and interpret them using ionic equations to emphasise the role of H+(aq)5.4 Write a balanced equation for the reaction between two elements and between an acid and a base