Covalent and Ionic Bonding

Mr Dunnum

Physical Science

Compounds

When elements form a compound the compound has properties that are very different from those of the elements that make it.

A compound is formed with chemical bonds

Bonding

Atoms bond when their valence electrons interact.

The outermost energy level of a bonded atom is full of electrons.

These bonds can be bent and stretched without breaking.

Covalent Bonding

CB is when electrons are shared

Nonmetal +Nonmetal Metalloid +Nonmetal

1st part of the name: write the name of the element, add the correct prefix if applicable (don’t add mono to 1st element)

2nd part of the name: use prefix and correct nonmetal ending (-ide)

Examples:

BCl3 Boron Trichloride

N2O5 Dinitrogen Pentoxide

Prefixes an suffixes

Prefixes – covalent compounds only

1 mono 2nd only

2 di

3 tri

4 tetra

5 penta

6 hexa

7 septa

8 octa

9 nona

10 deca

Suffixes

-ide

Indicates binary compound

-ite/-ate

Indicates presence of a polyatomic ion containing oxygen

-ite always has one less O than –ate but the number of O varies

Ionic Bonding

Metal and Nonmetal

Ionic bonding are formed by the transfer of electrons

Ionic characteristics

Conduct electricity when melted or dissolved in water

Solid Ionic compounds have high melting point

Naming Ionic Compounds

Metal + Nonmetal

Write the name of the metal

Examples:

Fe2O3 has Fe +3 ions, named iron (III) oxide

FeO has Fe +2 ions, named iron (II) oxide

Transition elements (3-12) oxidation number may very

Zn is always +2 and Ag is always +1

Write the name of the nonmetal with the “-ide” ending

Examples:

LiF Lithium Fluoride

MgS Magnesium Sulfide

-When naming them backwards cross check oxidation numbers

Polyatomic Ions

Polyatomic Ions + Nonmetal (more than 2 elements)

When a polyatomic ion is present, write its name as is and use rule above for metal and nonmetal endings

Examples:

(NH4)2S Ammonium sulfide

NaNO3 Sodium nitrate (ending is polyatomic ion’s name)

(NH4)2SO4 Ammonium Sulfate

An ion made of two or more atoms that are covalently bonded and that act like a single ion, metal + nonmetal.

Put parentheses around the group representing the polyatomic ion