Rules for Sig. Digs Essays - Chemical Bonding, Valence Electron

Rules for Sig. Digs Essays - Chemical Bonding, Valence Electron Rules for Sig. Digs All digits from 1-9 are sig. Zeroes btwn the digs. 1-9 are sig. Leading 0s sig. If there is NO decimal pt, trailing 0s are sig. If there is a decimal pt, trailing 0s are sig. When + and round to lowest sig. dig. Period A row in the periodic table Group A column in the periodic table Valence Electrons Electrons in the outermost shell of an atom Nomenclature Ionic Compounds Write symbols for each element Write charge for element above its symbol Cross the numbers from the charges over to the other element to make a subscript Change the ending to -ide Latin Names Iron= Ferric/Ferrous Copper= Cupric/Cuprous Tin= Stannic/Stannous Gold= Auric/Aurous Mercury= Mercuric/Mercurous Lead= Plumbic/Plumbous Polyatomic Compounds *Recognize the groups of atoms that act as one ion* OH NICK the CAMEL had a CLAM for SUPPER in PHOENIX *exception Ammonium* Molecular Compounds Use prefixes Mono-1 Di-2 Tri-3 Tetra-4 Penta-5 Hexa-6 Hepta-7 Octa-8 Non-9 Deca-10 Element closest to the left goes first Scientific Notation Notation based on powers of 10 Sig. dig. X 10# of times decimal moved Exponent Examples 3 43 = 192 4x3 2x3 = 8x6 x5 x3 = x8 65/63 = 62 x4/x7 = x-3 = 1/x3 80 = 1 (y4)3 = y12 Matter Pure Substance A material that is composed of only one type of particle Mixture A material system made up of two or more different substances which are mixed but are not combined chemically Element Primary constituents of matter Compounds Consists of two or more different atoms Homogenous A homogeneous mixture is any mixture that is uniform in composition throughout Heterogeneous A heterogeneous mixture is any mixture that is not uniform in composition Diagrams Lewis Dot Element symbol and valence electrons Bohr Rutherford In the nucleus (#of neutrons, #of protons) Electrons circling in shells Periodic Trends Atomic Radius The distance from the centre of the atom to the boundary within which electrons spend 90% of their time Trends in A.R within a Period The radius increases going from left to right Trends in A.R within a Group Size of radius increases going down a group Ionization Energy The amount of energy required to remove the outermost electron from the atom or ion in a gaseous state Electronegativity An indicator of the relative ability of an atom to attract shared electrons Trends in E.N E.N increases going up a group E.N increases going left to right across a period Highest E.N: Fluorine Lowest E.N: Francium Metal Reactivity Trend Moving left to right across a period reactivity increases Moving down a group reactivity decreases Metallic Properties Trend Tend to decrease across a period and increase down a group Atomic # The number of protons Atomic Mass The mass of an atomic particle Isotope An atom with different numbers of neutrons Ion An atom that has gained or lost an electron Trends in Electron Configuration Elements in the same group have the same # of valence electrons Across a period # of valence electrons increase Valence electrons in a period occupy the same energy level Down a group the energy of the valence shell electrons increases Covalent Bond Angle Summary IVVVIVII 4 bonds3 bonds2 bonds1 bond Ionic Bonds Between a metal and a non-metal High melting and boiling points Conductive when liquid Covalent Bonds Between 2 non-metals Low melting and boiling points Poor Conductivity Soft or brittle solid forms Noble Gases Group 18 elements Full octet Does not bond Stable, non- reactive Halogens Group 17 elements 7 valence electrons Reactive Non-metals Alkali Metals Elements in group 1 (except for hydrogen) 1 valence electron Very reactive Alkaline Earth Metals Elements in group 2 2 valence electrons Semi reactive Lanthanides Period 6 Rare earth elements Inner transition elements Actinides Period 7 Have no stable isotopes Radioactive Transition Metals Groups 3 through 11 Hard metals High melting points Complex electron configuration Non-metals Semi reactive Most common in the tissue of living organisms Metalloids Share properties of metals and non-metals Poor conductors Polarity The physical alignment of atoms Can be predicted using the electronegativity difference of the elements that are bonded Polar Covalent Unequal sharing Nonpolar Covalent Equal sharing Metallic Bonding Occurs between atoms with low electro negativities Close-packed lattice formation No electron belongs to one atom Metallic bonds are not ions, but nuclei with moving electrons Physical Properties of Metallic Bonds Conductive Lustrous Malleable The greater the amount of valence electrons the stronger the metallic bond VSEPR Theory V: Valence S: Shell E: Electron P: Pair R: Repulsion Because of negative charges, atoms orient themselves as far apart as possible Electron Affinity The energy absorbed or released when an electron is added to a neutral atom The Octet Rule When bonds form between atoms, the atoms gain, lose, or share, electrons in such a way that they create a filled outer shell containing eight electrons Single Bond A covalent bond that results from atoms sharing one pair of electrons Double Bond A covalent bond that results from atoms sharing two pairs of electrons Triple Bond A covalent bond that results from the atoms sharing three pairs of electrons Bonding Pair A pair of electrons that is shared by two atoms, thus forming a covalent bond Lone Pair A pair of electrons that is not part of a covalent bond Electronegativity Difference The difference between