Chemistry 3 A Objectives Compounds A pure substance

Chemistry 3 A Objectives

Compounds • A pure substance made of two or more kinds of elements. • When the two elements combine, the atoms of one element connect with the atoms of another element. • Chemical bonds hold the atoms together

Compound Formula Ex: Water (H 2 O) Elements are Hydrogen and Oxygen The 2 below the H (subscript) means that there are 2 Atoms of hydrogen. When there is no number written as a subscript it means 1 atom. In this example there is 1 atom of oxygen.

Draw a Molecule of Water

Hydrochloric Acid (HCl) • How many elements? • How many atoms? • Draw Ball & Stick Model

Compound Worksheet • Identify the elements, atoms, and draw a ball and stick model diagram for each compound. • Bill Nye Video: Atoms

Compound Types • Ionic Compounds • Molecular or Covalent Compounds

Ionic Compounds “Salts” • Metal + Non-Metal • Opposites attract • Atoms will gain or lose electrons to form ions (Think back to your Bohr diagrams) • Ex: Na. Cl

Examples of Ionic Compounds • Mg. Cl 2 • KBr • Na 2 O

Common Ionic Compounds (Memorize) • Table salt (sodium chloride) Na. Cl • Calcium carbonate Ca. CO 3 • Sodium hydroxide Na. OH

Molecular Compounds • Non-metal + Non-metal • Atoms share electrons to form a molecule • Ex: Methane (CH 4)

Examples of Molecular Compounds • SO 2 • N 2 I 3

Common Molecular Compounds (memorize) • • Sucrose or table sugar C 12 H 22 O 11 Carbon dioxide CO 2 Methane CH 4 Water H 2 O

Worksheet • Identify the following compounds as ionic or molecular.

Naming Ionic Compounds 1. Write the Metal name first 2. Write the Non-metal name but change its ending to “ide”. Ex: If you were joining the elements magnesium and oxygen. It would be named Magnesium oxide

Name the Ionic Compounds • Mg. Cl 2 • KBr • Na 2 O

Textbook Practice Problems • Page 82

Naming Molecular Compounds 1. Name the first element in the compound. ( if there is more than one atom of the 1 st element, add in the prefix. If there is only one don’t use prefix on first element ) **Prefix is written at the start of the name Ex: diphosphorus

2. Name the second element and switch the ending to“ide” (add a prefix to the second element based on how many atoms are there) Ex: trioxide

Molecular Compounds Memorize Prefix’s 1 - mono 6 - hexa 2 – di 7 - hepta 3 – tri 8 - octa 4 - tetra 9 - nona 5 – penta 10 - deca

Example NO 3 Two non-metals = molecular compound N is nitrogen. O is oxygen. 1 atom of nitrogen and 3 atoms of oxygen Name: nitrogen trioxide. **Don’t use mono on the first element when naming.

Example S 2 O 5 disulfur pentaoxide

Name these Molecular Compounds • SO 2 • N 2 I 3

Textbook Practice Problems • Page 83

Compound Worksheet • Naming Compounds

Compound Assignment