Science Study Guide

• Ionic bonds


  -bonds formed between metals(M) and non-metals(NM)
• Bonds

  Interactions between atoms involving valance electrons
• Lewis Dot Diagram


  Simple way to show valence electrons
• Ionic bond formation


  1. Atom gives away electron

  2. Opposites attract
• Ionic Bond Groups


  • Group 1+2 (alkali & alkaline earth metals)
  • Group 16+17 (oxygen family, halogens)
• Electronegativity increases from left to right on the periodic table

  Because further along the atoms gain more valance electrons and want to complete the full outer shell to become stable.
• Electronegativity decreases from top to bottom on the periodic table

  This is because further down it has more rings and is less likely to need to steal other electrons.
• Ionization energy decreases from left to right on the periodic table
• Ionization energy increases from top to bottom on the periodic table
• Atomic radius decreases from left to right on the periodic table

  This is because the atom gains more electrons and protons, creating a greater electric charge from attraction, therefore making it smaller.
• Atomic radius increases from top to bottom on the periodic table

  This is because the atom gains more rings and layers, so the atom will have a larger radius
• Electronegativity


  An atom's ability to take an electron from another atom
• Highest electronegativity: Fluorine (F)
• Lowest electronegativity: Francium (Fr)
• Highest ionization energy: Helium (He)
• Lowest ionization energy: Francium (Fr)
• Each row of the periodic table adds a new electron orbital
• The number of protons never changes in an element, but neutrons and electrons can change
• Electron theory


  Electrons are the foundation of chemistry and the most important part of an atom
• The first electron orbital can hold 2 electrons, the second can hold 8 electrons, the third can hold 8 electrons.
• Atoms in the neutral state have the same number of protons and electrons
• Filling electron orbitals


  Fill from closest to nucleus, outwards
• Naming Ionic Compounds


  1. Write the symbol of the metal first, followed by the symbol of the nonmetal

  2. Write the name of the metal, then add the name of the nonmetal with the suffix -ide
• Ions


  • Cation (+) usually metals because they give electrons and end up with one extra positive.
  • Anion (-) usually non-metals because they gain one or more electrons from metals during bonding giving them extra.
• Elements

  Pure substances that are all made up of only one type of atom. All of the atoms on the periodic table are pure elements.
• Compounds

  A pure substance made of 2 or more atoms that are chemically combined in a set ratio. Compounds are represented in a chemical formula that shows what elements and how many of each.
• Mixture

  A substance made up of 2 or more atoms that are together in the same place, but their not chemically bonded.

  Heterogenous

  Homogenous
• Heterogenous Mixture

  A mixture of 2+ atoms not chemically bonded. You can easily tell the difference between each substance and separate them.

  Ex: Chocolate Chip Cookies, Trail Mix, Cereal and Milk
• Homogenous Mixture

  A mixture of 2+ atoms not chemically bonded. It is difficult to separate or tell the difference between them.

  Ex: Cake Mix, Coffee, Wind
• Reactivity:


  -The ease and speed with which an element combines, or reacts, with other substances.

  -Elements with less valence electrons are more reactive
• Malleable:


  One that can be hammered or rolled into flat sheets or other shapes.

  Physical Property
• Ductile


  One that can be pulled out, or drawn, into long wires.

  Physical Property
• Thermal/Electrical Conductivity:


  The ability of an object to transfer heat/energy.

  Physical Property
• Luster:


  The amount of shine and reflectivity.

  High- Very shiny

  Low- Dull/Matte

  Physical Property
• Nonmetal Physical Properties:


  -Lacks most of the properties of a metal

  -Poor conductors of electric current and heat

  -Solid nonmetals tend to be dull and brittle

  -Most break/crumble into a powder when hit

  -Many are gases at room temperature
• Physical Properties:


  -Can be observed without changing the identity of the substance

  Luster

  Melting/Boiling Points

  Malleability

  Ductility

  Solid/Liquid/Gas

  Density

  Solubility

  Odor
• Chemical Properties:


  -Can ONLY be observed by changing the identity of the substance

  Flammability- light on fire to figure out

  Combustibility- how it reacts with oxygen

  Toxicity- poison

  pH- acidity

  Reactivity with water, air, acids, etc.

  Ability to rust
• Metal Chemical Properties:


  1-3 Valence electrons

  Don't react with other metals

  Metals with only one valence electron are especially reactive

  Most are Crystalline solids

  Metal Crystals-closely packed, positively charged metal atoms.
• Metalloids:


  -have properties of metals and non-metals

  -brittle, hard, some-what reactive

  -most common(Silicon)

  -most useful property- electric conductivity

  -semiconductor- substance that can conduct electricity under some conditions and can't in others.
• when bonding occurs, the resulting compounds have properties that are different from the elements that make it up.