Lewis Dot Diagrams LEWIS DOT DIAGRAMS 1 Find

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Lewis Dot Diagrams

Lewis Dot Diagrams

LEWIS DOT DIAGRAMS 1. Find the valence electrons. 2. Write the element symbol. 3.

LEWIS DOT DIAGRAMS 1. Find the valence electrons. 2. Write the element symbol. 3. Draw the dots starting at the top right of the symbol.

EXAMPLE – Carbon (Element #6) 1. Find the valence electrons. 2. Write the element

EXAMPLE – Carbon (Element #6) 1. Find the valence electrons. 2. Write the element symbol. • Carbon has 4 valence electrons because it is in group 14. • Element symbol is C. 1 3. Draw the dots starting at the top of the symbol and continuing clockwise. 2 4 3 Pretend like there’s an imaginary box around the letters

EXAMPLE – Sulfur (Element #16) 1. Find the valence electrons. 2. Write the element

EXAMPLE – Sulfur (Element #16) 1. Find the valence electrons. 2. Write the element symbol. 3. Draw the dots starting at the top right of the symbol and continuing clockwise. • Sulfur has 6 valence electrons because it is in group 16. • Element symbol is S. 1 5 2 4 6 3

OTHER EXAMPLES Bromine has seven valence electrons because it’s in Group Seventeen Boron has

OTHER EXAMPLES Bromine has seven valence electrons because it’s in Group Seventeen Boron has three valence electrons because it’s in Group Thirteen Copper has one or two valence electrons because it’s a transition metal

FOR YOU TO TRY… How many valence electrons does tin have? 4 because it’s

FOR YOU TO TRY… How many valence electrons does tin have? 4 because it’s in Group Fourteen How many valence electrons does calcium have? 2 because it’s in Group Two How many valence electrons does Krypton have? 8 because it’s in Group Eighteen

Classwork • Draw the Lewis Dot Diagrams for neutral atoms of the following elements:

Classwork • Draw the Lewis Dot Diagrams for neutral atoms of the following elements: –F – Al – Si –K – Mg –N –O

Lewis Structures Lewis

Lewis Structures Lewis

Lewis Structures • A Lewis structure is a twodimensional representation of a molecule •

Lewis Structures • A Lewis structure is a twodimensional representation of a molecule • Lewis structures have a systematic method used to determine how they should be written

Ionic Compounds Vs Covalent (Molecules) Compounds

Ionic Compounds Vs Covalent (Molecules) Compounds

B. Types of Bonds IONIC COVALENT e- are transferred from metal to nonmetal e-

B. Types of Bonds IONIC COVALENT e- are transferred from metal to nonmetal e- are shared between two nonmetals Type of Structure crystal lattice true molecules Physical State solid liquid or gas Melting Point high low Solubility in Water yes usually not Electrical Conductivity yes (solution or liquid) no Bond Formation Other Properties C. Johannesson odorous

B. Types of Bonds METALLIC Bond Formation e- are delocalized among metal atoms Type

B. Types of Bonds METALLIC Bond Formation e- are delocalized among metal atoms Type of Structure “electron sea” Physical State solid Melting Point very high Solubility in Water no Electrical Conductivity yes (any form) Other Properties malleable, ductile, lustrous

Rules for writing ionic compound Lewis structures 1. Determine that a metal is present

Rules for writing ionic compound Lewis structures 1. Determine that a metal is present / first element on left of periodic table(Not counting H). 2. Write the Lewis structures for the elements in the ionic compound. 3. Draw an arrow showing the transfer of the electrons from the metal (low electronegativity element) to the non-metal (high electronegativity. )

Ionic Compounds

Ionic Compounds

Lewis Structures • Sum the valence electrons from each atom – Valence electrons can

Lewis Structures • Sum the valence electrons from each atom – Valence electrons can be found from group number • Use a pair of electrons to form a bond between each pair of bound atoms • Arrange the remaining electrons to place 2 electrons around period 1 elements and 8 electrons around other period elements • Resonance: when multiple Lewis structures exist for the same compound

Practice • • PCl 3 • Br 2 NI 3 • H 2 O

Practice • • PCl 3 • Br 2 NI 3 • H 2 O • O 2 NO+ SCN- (C is the central atom) • HCl • Cl. F

More Examples 1. 2. 3. 4. 5. 6. NH 4+ CO 2 CNCl 2

More Examples 1. 2. 3. 4. 5. 6. NH 4+ CO 2 CNCl 2 HCN Cl. O 3–

Homework • • HF N 2 NH 3 CH 4 CF 4 NO+ NO

Homework • • HF N 2 NH 3 CH 4 CF 4 NO+ NO 3 -

Lewis Structures Exceptions • Octet rules fails – Molecules with an odd number of

Lewis Structures Exceptions • Octet rules fails – Molecules with an odd number of electrons Examples: Cl. O 2 – Molecules in which an atom has less than an octet Example: BF 3 – Molecules in which atom has more than an octet Example: PCl 5 – Practice Draw the Lewis structure for ICl 4–

Practice • Draw the Lewis Structures for the following compounds: – – – I

Practice • Draw the Lewis Structures for the following compounds: – – – I 2 Si. O 2 Cl. F 3 Xe. O 3 Rn. Cl 2 Be. Cl 2

Resonance • A resonance structure is one of two or more Lewis structures that

Resonance • A resonance structure is one of two or more Lewis structures that have the same skeletal formula, but different electron arrangements. • The actual structure of the molecule is the intermediate between the two or more resonance structures and is called a resonance hybrid.

Resonance • Draw the Lewis structure for O 3 and include all possible resonance

Resonance • Draw the Lewis structure for O 3 and include all possible resonance structures.