Periodic Table Study Guide How to Draw Lewis Structures

Lewis Structures Determine the number of valence electrons. It is equal to the group #, or valence 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.

Groups - Review Group 8 = 8 electrons Group 1 = 1 electron Except for He, it has 2 electrons Group 2 = 2 electrons Each column is called a “group” 3, 4, 5, 6, 7 Each element in a group has the same number of electrons in their outer orbital, also known as “shells”. The electrons in the outer shell are called “valence electrons”

C Lewis Structures Write the element symbol. Carbon is in the 4th group, so it has 4 valence electrons. Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol. C

C Lewis Structures Check your work. Using your periodic table, check that Carbon is in the 4th group. You should have 4 total electrons, or dots, drawn in for Carbon. C

C Lewis Structures On your worksheet, try these elements on your own: P Ca Ar Cl Al C

H Lewis Structures On your worksheet, try these elements on your own: P Ca Ar Cl Al H

P Lewis Structures On your worksheet, try these elements on your own: Ca Ar Cl Al P

Lewis Structures On your worksheet, try these elements on your own: H P Ca Ar Cl Al

Ar Lewis Structures On your worksheet, try these elements on your own: P Ca Ar Cl Al Ar

Cl Lewis Structures On your worksheet, try these elements on your own: P Ca Ar Cl Al Cl

Al Lewis Structures On your worksheet, try these elements on your own: P Ca Ar Cl Al Al

Chemical Bonds

Learning Objectives Understand what a covalent bond is and what an ionic bond is and how they are different

Ionic Bond Between atoms of metals and nonmetals with very different electronegativity Bond formed by transfer of electrons Produce charged ions all states. Conductors and have high melting point. Examples; NaCl, CaCl2, K2O

Ionic Bonds: One Big Greedy Thief Dog!

Continuous Ionic Crystals

COVALENT BOND bond formed by the sharing of electrons of close electronegativity <0.7

Figure 12.3: Electronegativity values for selected elements. Copyright © Houghton Mifflin Company

Covalent Bond Between nonmetallic elements of similar electronegativity. Formed by sharing electron pairs Non-metals to non-metals Examples; O2, CO2, C2H6, H2O, SiC

Covalent Bonds

2. Covalent bonds- Two atoms share one or more pairs of outer-shell electrons. Oxygen Atom Oxygen Atom Oxygen Molecule (O2)

Covalent Bonds: Willing to share.