1. Lewis electron-dot diagram is a notation that shows symbol of an atom and dots equal to the number of valence electrons. Can be drawn for neutral atoms, ions and compounds Neutral atom Lewis dot diagram shows the symbol of the atom and dots equal to the number of valence electrons in the atom’s electron configuration Sodium2 – 8 – 1 Na ● Phosphorus2 – 8 – 5.. P :.

2. Positive ion Lewis dot diagram for a positive ion is the same as the symbol of the positive ion. Sodium ion 2 – 8 Na + Negative ion Lewis electron dot diagram for a negative ion must show the symbol of the ion and 8 dots. Hydride ion 2 H : - +2 Ca +2 is the correct symbol for a calcium ion. Ca It is also the Lewis dot diagram for a calcium 20

3. +2 Ca +2 is the correct symbol for a calcium ion. Ca It is also the Lewis dot diagram for a calcium 20 ion. Br Br - is the correct symbol for a bromine ion. 35.. - : Br : Lewis dot diagram for a bromide ion..

4. Lewis electron dot diagram for ionic formula must show the Lewis electron dot symbols for both the positive and negative ions of the ionic compound A correct Lewis electron dot symbol for a given ionic formula must show CORRECT positive ion symbol of the formula CORRECT negative ion symbol of the formula CORRECT number of dots around the negative ion of the formula CORRECT number of each ion in the formula

5. Draw the electron dot diagram for NaCl Step 1Draw Lewis dot diagrams for atoms... Na. Cl :.. Step 2Show electron transfer x ------- .. Na. Cl :.. Step 3Show ions to complete diagrams.. - [Na + ] [: Cl :]..

6. Practice Draw the electron dot diagram for CaBr 2 Draw the electron dot diagram for K 2 O

7. Lewis electron dot symbols for covalent bonding and molecules Each pair of electrons shared between two atoms forms one (single) covalent bond. Lewis electron dot diagrams for covalently bonded atoms must show the sharing of electrons by the nonmetal atoms. A correct Lewis electron dot diagram for a molecular formula must show CORRECT symbols and number of the nonmetal atoms CORRECT number of shared electrons between the atoms CORRECT number of valence electrons around each atom

8. Lewis electron dot diagrams for diatomic molecules Step 1Draw symbols for both atoms H HO ON N Step 2Determine how many electrons MUST be put between the two atoms. H. xH.. xx O: x x O: N. : x x x N Step 3Complete each Lewis dot diagram H – H.. xx O = O :N = N:.. xx

9. Draw Lewis electron dot diagrams for each of the following common molecular substances Hydrogen chlorideHCl WaterH 2 O AmmoniaNH 3 ChlorineCl 2 Carbon dioxideCO 2 MethaneCH 4 Carbon tetrachlorideCCl 4

10. Practice Draw a Lewis electron dot diagram for a calcium atom. Draw a Lewis electron dot diagram for a strontium ion. Draw a Lewis electron dot diagram for a fluoride ion. Draw a Lewis electron dot diagram for strontium bromide. Draw a Lewis electron dot diagram for a diatomic molecule of fluorine.