Notes: Ionic Bonds and Lewis Dot Structures

How to Draw Lewis Structures

Lewis Structures

1) Find your element on the periodic table.2) Determine the number of valence electrons.3) This is how many electrons you will draw.

Lewis Structures

• Find out which group (column) your element is in.

• This will tell you the number of valence electrons your element has.

• You will only draw the valence electrons.

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Groups - Review

•Each column is called a “group”

•Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.

Group 1 = 1 electron

Group 2 = 2 electrons

Group 8 = 8 electrons

Except for He, it has 2 electrons

•The electrons in the outer shell are called “valence electrons”www.chem4kids.com

3, 4, 5, 6, 7

Lewis Structures1) Write the element

symbol.2) Carbon is in the 4th

group, so it has 4 valence electrons.

3) Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol.

C

Lewis Structures

C

1) Check your work.2) Using your periodic

table, check that Carbon is in the 4th group.

3) You should have 4 total electrons, or dots, drawn in for Carbon.

Lewis Structures

COn your worksheet, try these elements on your own:

a) Hb) Pc) Cad) Are) Clf) Al

Ionic Bonds

Bonding Atoms

• Why do atoms bond?- each atom wants a full outermost energy level - gain, lose, and share valence electrons to achieve the duet or octet rule aka: “being happy”- gives each atom an electron configuration similar to that of a noble gasex. Group 18: He, Ne, Ar

Chemical Bonds

Chemical Bonds- attractive force that holds atoms or ions together- 3 types

ionic, covalent, metallic- determines the structure of compound- structure affects properties

- melting/boiling pts, conductivity etc.

Ionic Bonds / Ionic Compounds• Definition

- bond formed by the attraction between oppositely charged ionscation: positive: lost e-’sanion: negative: gained e-’s- oppositely charged ions attract each other and form an ionic bondex. Na+ + Cl- = NaCl- electrons are transferred from one atom to another- negative ions attract more positive ions, and soon a network is formed

Networks / Crystal Lattices Networks

- repeating pattern of multiple ionsex. NaCl

- every Na ion is next to 6 Cl ions

- strong attraction between ions creates a rigid framework, or lattice structure: aka: crystals

ex, cubes, hexagons, tetragons

Properties of Ionic Compounds• Structure affects properties

- strong attractions between ions: strong bonds- high melting/boiling pt- shatter when struck (think of it as one unit)- conductivitysolid: ions are so close together, fixed positions, (can’t move) NO conductivityliquid: ions are freely moving due to a broken lattice structure Good conductivity