ELEMENTS – a review… • Made of individual atoms. • Cannot be broken down into simpler substances. • Listed on the periodic table. • Created to be the building blocks of all matter.
MIXTURES – a review… • Different substances just placed together. • Substances keep their individual properties. • Easily separated like sand and gravel.
COMPOUNDS • Two or more elements bonded together = COMPOUND. • Have properties different from the original element. • Have a chemical formula • Not easily separated. • New properties!!!! • Atoms are to elementsasmolecules are to compounds!!
MODELS OF COMPOUNDS A. BALL AND STICK B. SPACE FILLING C. STRUCTURAL FORMULA
STRUCTURE AND PROPERTIES A. Network structure - ATOMS SiO2 (strong, rigid, high melting point) EXAMPLE: B. Network structure - IONS NaCl (strong, rigid, high melting point) EXAMPLE: C. Molecule groups C12H22O11 (weak bonds, low melting point) EXAMPLE:
4.2 IONIC, METALLIC, AND COVALENT BONDING How could you get pieces of paper to bond (stick together)?
Atoms BOND (stick together) when their outer energy level (VALENCE) electrons interact.There will be THREE different kinds of bonding.
1. IONIC BONDS • Electrons are transferred from one atom to another creating ions. • Then the bond is formed between oppositely charged ions. • Ionic compounds are in the form of a network of particles. • Ionic compounds conduct electricity when melted or dissolved in water.
2. METALLIC BONDS • Electrons are free to move from atom to atom. • Atoms are tightly packed together. • Metals are: flexible, can bend and stretch, and can conduct electricity.
3. COVALENT BONDS • Formed when atoms share electrons. • Often form from nonmetals. • Most have low melting points. • Do not conduct electricity well.
NONMETAL METAL BONDING SUMMARY(how to tell what type of bond is holding a molecule together) Periodic Table METAL + NONMETAL =IONIC NONMETAL + NONMETAL = COVALENT METAL+ METAL = METALIC
POLAR DIFFERENT TYPES OF ATOMS DO NOT SHARE ELECTRONS EQUALLY NONPOLAR ATOMS OF THE SAME TYPE SHARE THE ELECTRONS EQUALLY POLAR AND NONPOLAR COVALENT BONDS
TYPES OF IONS CAtION – ION WITH A POSITIVE (+) CHARGE ANION – ION WITH A NEGATIVE (-) CHARGE
PERIODIC TABLE NONMETALS METALS NOBLE GA S TRANSITION METALS +1 +2 -2 -1 +1 OR +2 CATIONS ANIONS
NAMING IONIC COMPOUNDS (Na+) NaCl (Cl-) Sodium Chloride (Mg2+)Mg + F (F-) MgF2 Magnesium Flouride
NAMING COVALENT COMPOUNDS ELEMENTS GET A NUMERICAL PREFIX THAT INDICATES HOW MANY ATOMS ARE PRESENT – (table 4-7) ELEMENTS TO THE RIGHT ARE NAMED SECOND AND END IN “IDE”
4.4 ORGANIC COMPOUNDSWhat does it mean to be organic?This is the common definition…
In Chemistry, an ORGANIC COMPOUND… • Contains the element CARBON and ALMOST always HYDROGEN. • CARBON is a SPECIAL ATOM: BECAUSE IT CAN BOND WITH FOUR OTHER ATOMS. (valence 4)
HYDROCARBONS • Contain ONLY HYDROGEN and CARBON
ALKANE – a special hydrocarbon • Hydrocarbons with SINGLE COVALENT BONDS • The simplest one is: CH4 = METHANE (table 4-9) • Others may form CHAINS, BRANCHES, or RINGS of hydrogen and carbon.
ALKENE – another type of hydrocarbon • A hydrocarbon with DOUBLE COVALENT BONDS C2H4 = ETHYLENE
ALCOHOL – another organic molecule • Alcohols contain the: (OH) atom group • CH3OH = METHANOL • The rest just add (OH) to the appropriate alkane in table 4-9….
POLYMERS • SMALL ORGANIC MOLECULES THAT BOND TO FORM LONG CHAINS OF MOLECULES: C2H4….= POLYETHYLENE • Some polymers are NATURAL CREATIONS of God: WOOD, STARCH, PROTEIN. • Some polymers are MAN-MADE: PLASTICS
CHAPTER FOUR TESTSTUDY THIS: • MIXTURE or COMPOUND • NETWORK structure or MOLECULE group • IONIC bond or COVALENT bond • Will a substance conduct electricity? Explain. • Chapter vocabulary words • ION location on the Periodic Table (notes)