Atoms, Molecules and Ions

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Atoms, Molecules and Ions. Grade VIII Semester 1 2010/2011 Abdul Malik SR Junior High School 1 Lamongan. Objectives. To define the meaning of particles of matter (atom, ion and molecule) To explain the difference of isotope, isotones and isobar - PowerPoint PPT Presentation

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<p>Atoms, Molecules and Ions</p> <p>Atoms, Molecules and IonsGrade VIII Semester 12010/2011Abdul Malik SRJunior High School 1 Lamongan</p> <p>1ObjectivesTo define the meaning of particles of matter (atom, ion and molecule)To explain the difference of isotope, isotones and isobarTo explain the difference between the element molecule and the compound moleculeTo mention some examples of simple molecules in daily lifeTo give examples of substances that consist of ions</p> <p>2Particles of matterOn grade VII you learned that all matters around us are made up of fundamental matter called ELEMENT.Element is a simple substance whch cannot be broken down into simpler subtances</p> <p>Look at the figure !</p> <p>A piece of iron is composed of a mass of iron atoms</p> <p>3What is an atom???Atom is the smallest unit of an element, having the properties of that element.</p> <p>This is atom Fe ( iron )FeDemocrituss model ( the father of atomic theory)FeFeFeFeFeFe</p> <p>4How has the model of the atom changed over time ?Daltons ConceptDaltons model 1807John Dalton, an English schoolteacher in the early nineteenth century, combined the idea of elements with the earlier theory of the atom. He proposed the following ideas about matter: Matter is made up of atoms, Atoms cannot be divided into smaller pieces, All the atoms of an element are exactly alikeDifferent elements are made of different kinds of atoms.</p> <p>5Thomsons model 1903Atom is continuous mass of positive charge containing negative electronRaisin pudding model</p> <p>6Rutherfords model 1903Atom has a nucleus surrounded by electrone- e- e-e-e- e-e-e-e-7Niels Bohrs model 1913Atom has a nucleus. Electrons move in fixed orbits around the nucleuse-e-e-nucleus8</p> <p>Structure of atoms</p> <p>THE STRUCTURE OF ATOMSAtoms are made up of three subatomic particlesProtons carry positive chargeNeutrons having no chargeElectrons carry negative charge</p> <p>The protons and neutrons are tightly bound together to form the central portion of an atom called the nucleus.The electrons are located outside of the nucleus and thought to move very rapidly throughout a relatively large volume of space surrounding the small but very heavy nucleus.</p> <p>9 The comparison of particles in atomparticleschargePosition in atomProtonNeutronelectron+1No charge- 1Atom nucleusAtom nucleusMoving around atom nucleus</p> <p>10Atomic Mass</p> <p>11ISOTOPESIsotopes are atoms with the same atomic numbers but different mass numbers.EXAMPLESHydrogen </p> <p>Chlorine</p> <p>Carbon</p> <p>12ISOBARAtoms of different elements might have the same mass number.EXAMPLES</p> <p>ISOTONESAtoms of different elements might have the same number of neutronEXAMPLES</p> <p>13Electron ArrangementAccording to Bohr, electrons move around the nucleus in fixed orbit or shellsThe electron in each shell have different energy level. The shells closes to the nucleus have lower energy levels than those farther awayThe biggest atoms can have up to 7 electron shells,However, each shell can contain only a limited number of electrons. This number depends on their size:1st shell maximum filled with 2 electrons.2nd shell maximum filled with 8 electrons.3rd shell can hold up to 18 electrons, but normally only holds up to 8 to make atom more stable. 4th shell can hold up to 32 electrons but, like the third shell, normally holds only up to 8 to make atom more stable14Example of Electron arrangementSodiump=11 e=11 n=12 </p> <p>Electronic Configuration: 2, 8, 1 1st shell2nd shell3rd shellElectronic Structure</p> <p>The electron in the outermost shell of an atom are called the outer electron or valency electronsSodium has 1 valency electron15</p> <p>16When atoms lose or gain electrons, they become ions</p> <p>ionsIon is an atom having electric chargeatomLoses electrons+Positive ion_Negative ionAn atom may gain or lose electronsGains electronscation ion with a positive chargeIf a neutral atom loses one or more electrons it becomes a cation.anion ion with a negative chargeIf a neutral atom gains one or more electrons it becomes an anion.Na11 protons11 electronsNa+11 protons10 electronsCl17 protons17 electronsCl-17 protons18 electronsPredicting Ionic ChargeMetals tend to form cations (group 1 and 2)Non-metals tend to form anions.(group 5, 6, 7 )</p> <p>Be2+19A monatomic ion contains only one atomA polyatomic ion contains more than one atom2.5Na+, Cl-, Ca2+, O2-, Al3+, N3-OH-, CN-, NH4+, NO3-</p> <p>201. Why do atoms bond together? Atoms bond to become more stable, like Noble Gases. </p> <p>21</p> <p>1. Ionic bonds Ionic bonds are formed by one atom transferring electrons to another atom to form ions. Ionic Compound A compound that contains positively charged ions and negatively charged ions.</p> <p>+Ionic Compoundsoften a metal + nonmetalanion (nonmetal), add ide to element nameBaCl2barium chlorideK2Opotassium oxideMg(OH)2magnesium hydroxideKNO3potassium nitrate2.7232. Covalent Bonding Covalent bonds are formed by atoms sharing electrons to form molecules. This type of bond usually formed between two non-metallic elements.(between 2 gass)</p> <p> Example:Two hydrogen atoms (1) form the molecule of the element hydrogen H2</p> <p>Two chlorine atoms (2.8.7) form the molecule of the element chlorine Cl2</p> <p>+</p> <p>+</p> <p>Another examples of covalent bond:Oxygen (o2)Water (H2O)Ammonia (NH3)Carbon Dioxide (CO2)25Comparison properties of ionic and covalent compoundIonic CompoundCovalent CompoundElectrical ConductivityConduct electricity when dissolved in waterDoes not conduct electricity in any stateMelting point and boiling pointHighLowSolubility in waterMostly solubleMostly insoluble26C. MoleculeA molecule is made up of two or more atoms chemically combined together.Molecules of Element Molecules are made up of the same kinds of atomsMolecules of CompoundsMolecules are made up of two or more different kinds of atoms</p> <p>27</p> <p>MOLECULES OF ELEMENT</p> <p>MOLECULES OF COMPOUND28The using of ions and molecules in chemical product in daily lifeComposerProductPolyvinyl Chloride (PVC)Water pipe, tilePolyetileneCarpet, laboratory apparatus</p> <p>Isoprene (C5H8) and polystyreneRubberSucrose (C12H22O11)Sugar, SyrupIonic compound NaClTable saltIon-ion (Cl-, Na+,Mg 3+, Ca2+)Isotonic drinks</p> <p>29</p>

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