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Elements Combine to Form Compounds. Name the Super – Heroes.

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Presentation on theme: "Elements Combine to Form Compounds. Name the Super – Heroes."— Presentation transcript:

1 Elements Combine to Form Compounds

2 Name the Super – Heroes

3 Compound – “Pun”

4 Compound - “Pun”

5 Compounds ( 2 nd type of Pure Substance) Compound: a pure substance made up of more than one kind of element in which the atoms of the elements are joined together. Compounds form through chemical bonds: these are links between two or more atoms that hold the atoms together Two types of Compounds (chemical bonds) Ionic Compounds Molecular (covalent) Compounds

6 Compounds… Compounds are represented by a combination of element symbols known as a chemical formula: Chemical Formula (tells us): type of elements (atoms) proportion (number) of each atom involved Elements Present Proportion: (# of each element) CH4 Carbon and Hydrogen 1 carbon atom and 4 hydrogen atoms NaCl Sodium and Chlorine 1 sodium atom and 1 chlorine atom

7 Two types of compounds Molecular (covalent) compounds: formed between non- metals only this type of bonding involves sharing of electrons Examples: ( we need to know ) 1) Carbon Dioxide (gas) - CO2 2) Water - H 2 O 3) Sucrose (table sugar) – C12H22O 11 4) Methane (gas) – CH4

8 Ionic Compounds formed between metals and non-metals. this type of bonding involves atoms attracting to each other because of opposite charges (+) (-) the atoms involved either gain or loose electrons to form charged particles called Ions (positive or negative) Examples: (we need to know) 1) Sodium Chloride (salt) - NaCl 2) Calcium Carbonate (chalk) - CaCO3 3) Sodium Sulfate (salt) - Na2SO4 4) Sodium Hydroxide (drain cleaner) – NaOH

9 Molecular (Covalent) “share” Ionic “give away and “charge”

10 Ionic Compounds - “Ions”

11 Counting Atoms Chemical FormulaElements InvolvedNumber of Atoms CO2Carbon (C) Oxygen (O) 3 atoms - 1 carbon (C) - 2 oxygen (O) MgClMagnesium (Mg) Chlorine (Cl) 2 atoms - 1 magnesium (Mg) - 1 chlorine (Cl) Na2SO4Sodium (Na) Sulphur (S) Oxygen (O) 7 atoms - 2 Sodium (Na) - 1 Sulphur (S) - 4 Oxygen (O ) C12H22O11Carbon (C) Hydrogen (H) Oxygen (O) ??? atoms – ___ carbon (C) ___ hydrogen (H) ___ oxygen (O)

12 Chemical Formulas

13 Chemical Names of Compounds When given a chemical formula, you can write the chemical name which indicates the elements present in the compound IUPAC (International Union of Pure and Applied Chemistry) a group that represent chemists around the world and is responsible for the rules when naming compounds. Ionic and Molecular compounds have their own set of rules to follow.

14 Naming Compounds Set of rules that you have to follow when writing the names for Ionic and Molecular Compounds. Basic steps: determine the elements involved in the chemical formula (compound)…. Metals and Non- Metals determine the type of compound (Ionic or Molecular) follow the rules outline for Ionic or Molecular

15 Naming Ionic Compounds formed between metals and non-metals. Rules: 1) Name the first element (atom) 2) Name second element by ending the name with the suffix “ide” 3) Put the two names together

16 Example of a Ionic Compound Example : name for the compound NaCl Na (sodium) - metal Cl (chlorine) - non- metal Name: Sodium chloride

17 Naming Molecular (covalent) Compounds formed between non-metals. numbers (subscripts) are important and have to be used at the beginning of each element in the naming of the compound. ……(see page 83) Rules: 1) Name the first element (atom) 2) Name second element by ending the name with the suffix “ide” 3) Add the “prefix” to the element names to show the number of atoms in the compound

18 Example of a Molecular (covalent) Compound Example : name for the compound CO2 C (carbon) - non-metal O (oxygen) – non- metal CO2 [Have to use Prefix to show number of atoms in compound] Name : Carbon dioxide

19 Prefixes (table 3.4, page 83) Number of atoms Prefix 1Mono (used only for the second atom) 2di 3tri 4tetra 5penta 6hexa 7hepta 8octa 9nona 10deca

20 Name the following compounds Mg 3 P2 Mg (metal) P (non –metal) ….. Ionic Magnesium Phosphorus Numbers are NOT important … Name: Magnesium phosphide

21 Name the following Compound N 2 O3 N (non-metal) O (non-metal) …..Molecular (Covalent) Nitrogen Oxygen Numbers are important N2O3 Name : Dinitrogen trioxide

22 Try These ??? 1) Ag 3 N - 2) CCl4 -

23 Physical Changes Physical Change a change in matter in which NO new substances are produced the appearance of a substance may be changed but the bonds between the particles (atoms) have not broken atoms either move closer together or farther apart Examples - change of state [freezing, melting …] - dissolving [sugar in water] - cutting paper

24 Chemical Changes Chemical Change a change in matter in which NEW substances are produced with NEW properties. Clues that May Indicate a Chemical Change A new color appears Heat or light is given off during the change Bubbles or gas are formed Solid clumps (precipitate) forms in the liquid The change is difficult to reverse Examples: - Corrosion [metals rusting] - Combustion [burning] - Fruit Ripening


26 Chemical Changes and Chemical Reactions Chemical Changes also referred to a Chemical Reaction In every chemical reaction there is something used up and something produced (made) Reactants Products Magnesium + Hydrochloric Acid → Hydrogen + Magnesium Chloride Sodium + Chlorine → Sodium Chloride

27 The END !!!!!

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