CHEM 102 1st Edition Lecture 1Outline of Last Lecture I. Overview of the syllabus and class expectationsOutline of Current Lecture I. Atoms and their structurea. Definitions of electrons, protons and neutronsb. Ions and their chargesII. How to write Element’s symbols a. Definitions of Atomic number and Mass numberb. Examples of where to put the numbersIII. Isotopesa. Definition of Isotopeb. How to write symbols for isotopesIV. The Periodic TableA. How it is organizedCurrent LectureAtomic Composition and Structure Atoms are made up of three different subatomic particles which include… Electronso Charge of negative oneo Weighs the least out of all three subatomic particleso Found in the electron cloud Protons o Charge of positive oneo Weighs the second most out of all three subatomic particleso Found in the nucleus of the atom Neutronso Charge of 0o Weighs the most out of all three subatomic particles o Found in the nucleus of the atomo 10 million times smaller than diameter of atom but contains 99.99% the mass of the atomThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.*Neutral atoms have the same number of protons and electrons* In many chemical reactions, atoms can gain or lose electrons, producing charged particles called Ions. There are two types of ions called… Cations: positively charged and is formed when an atom loses one or more electrons Anions: negatively charged and are formed when an atom gains one or more electronsThe number of protons in the nucleus, or the Atomic Number, determines the symbol used for an ion. The element’s symbol is followed by a number and sign that shows on the ion in electroncharge units.- Ex. Na+, P -3- An element has 9 protons and 10 electrons, write the symbol: F -1 because there are more electrons than protons- See this http://upload.wikimedia.org/wikipedia/commons/3/38/Chemical_Principles,_Table_1.4.png for a chart of charges of different elements Atomic Number (Z): number of protons in the nucleus of an atom; determines the identity of anelement. See example here http://chemwiki.ucdavis.edu/@api/deki/files/8320/He_Atom.pngMass Number (A): the sum of the numbers of protons and neutrons in the nucleus. See link above.Isotopes: different atoms of the same element that have different numbers of neutrons (same Z, different A) *Nucleons- protons and neutrons found in the nucleus*You can identify different isotopes by looking at the different mass numbers (for isotopes only, mass numbers are on top and atomic numbers are on bottom). Since the atomic number will always be the same in isotopes, it is sometimes left out when writing the symbol. See this to seehow isotopes are written… http://www.sartep.com/chem/images/isotopes.gifEX. Write the Symbols of isotopes with…- 15 protons, 18 electrons and 16 neutrons (Don’t forget to write the charge!!!)*Find the number of neutrons by subtracting the atomic number from the rounded mass number*Periodic Table: arranges elements into rows that place similar elements in the same column Period: a horizontal row Group: a column with chemically alike elementsClassifications of ElementsMetal: a material that has luster and is a god conductor of electricity: metallic elements are on the center and left side of the periodic table Nonmetal: a material that is typically a nonconductor: top right section of the periodic tableMetalloid: element that has properties of metals and non-metalsGroups of ElementsAlkali Metals: soft, reactive metals in group IAAlkaline Earth Metals: elements in group IIAHalogens: Salt formers, reactive nonmetals in group VIIANobel Gasses: the stable, docile gases in group
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