Presentation on theme: "How Do We Make Compounds?. What is inside the atom? Atom: made of subatomic particles Proton (+) = atomic # : determines the identity of the element Neutron."— Presentation transcript:
How Do We Make Compounds?
What is inside the atom? Atom: made of subatomic particles Proton (+) = atomic # : determines the identity of the element Neutron (no charge) Electron (-) Atomic mass = protons + neutrons Periodic Table : arranged by Russian Chemist Dmitri Mendeleev, by atomic #
Why do atoms bond? Octet Rule: Every atom wants 8 electrons to fill the valence shell (outer most shell) Ion: Charged atom (Ca +2 ) Cation: + charged ion Anion: - charged ion Polyatomic Ion: Two or more atoms covalently bonded together to form an ion (SO 4 -2 )
What are Ionic, Covalent and Metallic Bonds? Ionic Bond: An electron is transferred from one element to another (metal to nonmetal) Covalent Bond: Electrons are shared (nonmetal to nonmetal) Metallic Bond: Sea of electrons (Metal to Metal)
Molecules and Molecular Compounds Properties of molecular compounds Low melting and boiling points Usually gas or liquid Composed of two or more nonmetals O 2, O 3, H 2 O
How Do We Name Molecular (covalent) Molecules? Name the first element Keep the root of the 2 nd element, drop the ending & add ide Now add the prefixes The first element does not need the prefix mono Prefixes: Mono (1) Di (2) Tri (3) Tetra (4) Penta (5) Hexa (6) Hepta (7) Octa (8) Nano (9) Deca (10) Name CO 2 Name CCl 4
How Do We Name Ionic Compounds? Name the first element. Use the root of 2 nd element and add ide (no prefixes) If there is a transition metal, determine the charge and add Roman Numerals If there is a polyatomic ion, name the first element and name the polyatomic ion. Name: CaCl 2, FeO, NaOH
Exceptions: Some of the transition metals have only one ionic charge: Do not use roman numerals for these: Silver is always 1+ (Ag 1+ ) Cadmium and Zinc are always 2+ (Cd 2+ and Zn 2+ )
What are Oxidation Numbers?
How do we draw a Lewis Dot Diagram? Determine the number of valence electrons Write the chemical symbol Place a dot for each valence electron around the symbol
Writing Chemical Formulas Rules of writing formulas: positive ion (cation) is written first … this is usually a metal negative ion (anion) is written second … this is usually a nonmetal subscripts are used to show how many ions of each part are in the compound. They are used to balance the charge of the ions.
Using the Criss Cross Method Determine the oxidation number (charge) on each ion. Write the chemical symbols of each ion (cation1 st,anion 2 nd ) Cross over the numbers ignoring the charges Reduce if necessary
HOW DO WE NAME BASES? BASES: USE SAME RULES AS NAMING COMPOUNDS EXAMPLE: NaOH SODIUM HYDROXIDE NOW YOU TRY: Ca(OH) 2 KOH Mg(OH) 2 CALCIUM HYDROXIDE POTASSIUM HYDROXIDE MAGNESIUM HYDROXIDE
HOW DO WE NAME ACIDS? ACIDS: AN ACIDS NAME COMES FROM THE ANION IT PRODUCES WHEN IT DISSOCIATES. HERE ARE SOME RULES; IF THE ANION ENDS IN IDE CHANGE IT TO IC AND ADD THE WORD HYDRO IN FRONT; HCl HYDROGEN CHLORIDE HYDROCHLORIC ACID IF THE ANION ENDS IN ATE, CHANGE IT TO IC AND DO NOT ADD A PREFIX H 2 SO 4 HYDROGEN SULFATE SULFURIC ACID IF THE NAME ENDS IN ITE, CHANGE IT TO OUS AND DO NOT ADD A PREFIx H 2 SO 3 HYDROGEN SULFITE SULFUROUS ACID