1. How Atoms Combine (7.3)

2. Atoms combine to become more ________. The most stable elements in the periodic table are the ___________________ because they have the maximum number of _____________ in their outermost orbits. (they have _____ valence electrons) There are 3 ways in which an atom that does not have a full valence shell can fill it: 1. it can __________ electrons, 2. it can __________ electrons, 3. it can __________ electrons. All 3 methods result in the formation of a chemical ___________. A chemical bond is the attraction between 2 _________. gain lose share atoms stable electrons 8 Noble gases bond Ionic bond covalent bond

4. IONIC BONDING Ionic bonds are formed between __________ elements and _____________ elements. Circle the compounds below that contain ionic bonds. KCl H 2 O O 2 MgO Na 2 S NH 3 Cl 2 Ionic bonds are formed by the attraction of 2 ____________ charged ions (an ion is a _________ particle). metal non-metal oppositely charged

5. 1117 Example 1: Sodium (Na) and Chlorine (Cl) NaCl +- IONIC COMPOUNDS

6. IONIC BONDING Example 1: Sodium (Na) and Chlorine (Cl ) the sodium atom its outermost electron to chlorine so that both atoms get a full outer shell (and become ___________). Sodium has lost an electron and now has a _____________ charge, while chlorine has gained an electron and now has a _____________charge. ______________ charged atoms ___________, forming an _____________ bond. loses stable positive negative oppositely attract ionic

7. IONIC BONDING 12 Example 2: Magnesium (Mg) and Fluorine (F) Mg F 9 9 F + - - +

8. IONIC BONDING Example 2: Magnesium (Mg) and Fluorine (F ) Magnesium needs to lose electrons. Fluorine needs to gain electron. Magnesium can only lose two electrons if it reacts with fluorine atoms. The formula for this compound is ___________ 2 1 2 MgF 2

11. Covalent bonds are formed from ____________ elements. Unlike ionic bonds that are formed from ions that have ______ or ________ electrons, covalent bonds are formed from atoms that _______ electrons. The attraction of 2 atoms for the shared pair of electrons results in a __________ bond. Two or more atoms joined by covalent bonds form a __________. non-metal lost gained share covalent molecule

12. Example #1:Hydrogen Molecule The hydrogen molecule consists of 2 hydrogen atoms. Each hydrogen atom has _____ valence electron. If each atom shares its electron with the other atom, then each atom has _____ electrons in their outer shell (1st shell). The shell is now full and the atoms (and molecule) are ______________. 1 2 stable

13. The formula for a hydrogen molecule is. H2H2 Bohr-Rutherford diagrams: Electron Dot diagrams: HHH H

14. Example #2:Hydrogen and Chlorine Hydrogen and chlorine each need more electron in order to have a full shell. They do this by one pair of. Electron Dot diagrams: HClH Cl The formula for the compound with hydrogen and chlorine is. 1 sharingelectrons HCl

15. Example #3:Hydrogen and Oxygen Hydrogen needs more electron in order to have a full outer shell. Oxygen needs ____ more electrons to have a full outer shell. Oxygen can get a full shell if it shares its 2 unpaired electrons with hydrogen atoms. This also gives each hydrogen atom a full outer shell. 1 2 2

16. Electron Dot diagrams: H OO HH The formula for the compound with hydrogen and oxygen is. This compound is known as ________. H2OH2O water

17. NOTE: When drawing electron dot diagrams for a molecule, use the stable octet rule. With the exception of hydrogen, each atom of the molecule should have 8 electrons (dots) surrounding it (including shared electrons).

18. Ionic Compounds Molecular (Covalent) Compounds Type of Bondsioniccovalent Types of Elements involvedmetals & non-metalsnon-metals only State at 20  C solidsolids, liquids, gases Forces between Ions or Molecules very strongweak Melting & Boiling Pointshighrelatively low Solubility in Watersolublemany are not soluble Conducts Electricity? solid – no liquids – yes dissolved in water - yes no Examples NaCl (salt) CaO AgNO 3 H 2 H 2 O CCl 4