Properties Elements Physical changes Usually dependent on conditions New substance NOT created Chemical h l changes h that substance Transforms in to something different that has new ELEMENTS COMPOUNDS AND MIXTURES Au Gold Li Lithium May have more than one atom to make molecules of A reaction occurs Chapter 14 Substances not bonded to other types of atoms May be single atoms in elemental formula properties O2 oxygen N2 nitrogen Or be macromolecules diamond crystals of C Compounds Classes of matter Properties of Compounds More than one type of atom in the molecule Has a Chemical Formula Very different from elements of their NaCl Ammonia A i NH3 Subscript tells how many of each Subscript 1 is omitted Sodium composition Sodium Chloride Chlorine Properties of Sodium Opaque soft shiny metal Very malleable can be cut with knife Tarnishes rapidly in air Melts at about Reacts violently with water 100OC Shiny soft metal metal melts at 97o C Reacts violently with water Substances MIXTURES Boils at 34o C Toxic gas Properties of Chlorine Properties of Sodium Chloride Yellowish gas at room temperature Toxic to organisms at low concentrations Clear brittle solid at room temperature Melts at 800o C Reacts readily with most other elements Characteristic odor Not toxic table salt Not reactive with water producing lye and hydrogen http en wikipedia org wiki Sodium http www amazingrust com Experiments how to Cl2 html http dharaniexim tradeindia com Exporters Suppliers Exporter19695 325973 Sodium Chloride html 1 Electron Shells Bonding of atoms makes molecules Causes of bonding Maximum number of The Formation of Ions and Ionic Bonds Types of bonds Metallic Bonds Covalent Bonds Polar Covalent Bonds Molecular Polarity and Molecular Attractions Full electron shells Outer electron shells of noble gases are full Electrons shells in periodic table Atoms bond together through their electrons Electrons behave as though they are contained within a series of seven concentric shells h ll Outer shell electrons interact with electrons of other atoms These are the VALENCE electrons Sodium Ion Formation Periodic table Ion An atom that has lost or gained one or more electrons Electron Dot Structure A notation showing only the valence electrons First three periods electrons in each shell is shown Inner shell fills up before next shell b i to t gett begins electrons Full shells are most stable Valence Electron dot structure for elements not in transition metal groups surrounding the atomic symbol 2 Ion Ion formation Ionic Bonds Lose electrons An atom molecule or compound with a different number of protons and electrons More protons positive CAT ION THE t looks like a plus sign More electrons negative AN ION Negative has an N in the prefix Both are all one word anion cation more protons than electrons positive charge Gain electrons More electrons than protons Negative charge More than one can be lost or gained Determine by position in periodic table Electrical force of attraction between oppositely charged ions Groups of atoms forming ions Ionic Bond Ratios Molecular Ions Compounds form in ratios to neutralize charges Molecular ions Bonds within group are covalent H H Water O H H Hydronium ion H3O Hydrogen ion Typically formed by the loss or gain of a hydrogen ion H Naming compounds first word Naming compounds second word Add the element more to Start with element more to the left side of periodic table Naming compounds NaCl Sodium Chloride the right on the periodic table change suffix to ide 3 Naming compounds Li2O Lithium Oxide Naming compounds CaF2 Calcium Fluoride Naming different compounds of same elements When more than one compound is formed from differing ratios of the same atoms a prefix is added to distinguish them Carbon Dio Dioxide ide Carbon Monoxide Naming Common Compounds Some have traditional names Water Ammonia Methane Nonpolar Covalent Bonds Polar Covalent Bonds Electrons are shared evenly when the two Shared unevenly when the bonded atoms are different elements atoms are the same element Propane etc Polarity of covalent bonds Closer together on the periodic table less polar bond Further apart on the periodic table more polar bond Molecules are called dipoles Ionic bonds are extremely polar beyond covalent 4
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