8th Grade Science

T. Trimpe 2008 http://sciencespot.net/

Section A: Complete the chart using a periodic table to help you.

Element

Atomic Symb

ol

Total # of electro

ns

# of Valance Electron

s

# of Electrons gained or

lost

Oxidation Numbe

r

Chlorine          

Potassium          

Magnesium          

Fluorine          

Aluminum          

Sodium          

Nitrogen          

Oxygen          

Carbon          

Iodine          

Section A: Complete the chart using a periodic table to help you.

Check your work!

Element

Atomic Symb

ol

Total # of electro

ns

# of Valance Electron

s

# of Electrons gained or

lost

Oxidation Numbe

r

Chlorine  Cl 17   7 1 gained   -1

Potassium K  19  1  1 lost +1 

Magnesium  Mg  12 2   2 lost +2 

Fluorine F  9  7  1 gained  -1 

Aluminum Al  13  3  3 lost  +3 

Sodium Na 11  1  1 lost  +1 

Nitrogen N  7  5  3 gained  -3 

Oxygen O  8  6  2 gained  -2 

Carbon C  6  4 4 gained or

lost  +/- 4 

Iodine I  53  7  1 gained  -1 

Answer these questions:

An atom that gains one or more electrons will have a ____________________ charge.

An atom that loses one or more electrons will have a ____________________ charge.

An atom that gains or loses one or more electrons is called an ____________.

A positive ion is called a ______________ and a negative ion is called an _______________.

POSITIVE

NEGATIVE

ION

CATIONANION

“An-Eye-On”“Cat-Eye-On”

What is an ionic bond?

Atoms will transfer one or more ________________ to another to form the bond.

Each atom is left with a ________________ outer shell.

An ionic bond forms between a ___________ ion with a positive charge and a ________________ ion with a negative charge.

ELECTRONS

COMPLETE

METALNONMETAL

Steps for Ionic Bonding1. draw dot diagrams2. Transfer Electrons with arrows 3. (Draw more dot diagrams)4. Write ions (atom with a charge.5. Formula- write it out!

Example B1: Sodium + Chlorine Example B2: Magnesium + Iodine

Example B3: Potassium + Iodine Example B4: Sodium + Oxygen

Example B5: Calcium + Chlorine Example B6: Aluminum + Chlorine

What is a covalent bond?

Atoms ___________ one or more electrons with each other to form the bond.

Each atom is left with a ________________ outer shell.

A covalent bond forms between two _________________.

SHARE

COMPLETE

NONMETAL

Steps for Covalent Bonding1. Draw dot diagrams2. Drw Circles ( e- that are shared)3. (Draw more dot diagrams)4. Line Drawings5. Formula- write it out!

Example C1: Hydrogen + Hydrogen Example C2: 2 Hydrogen + Oxygen

Example C3: Chlorine + Chlorine Example C4: Oxygen + Oxygen

Example C5: Carbon + 2 Oxygen Example C6: Carbon + 4 Hydrogen