ions and ionic bonding

Ionic Bonding

Section 6.1

Remember…?

• Sodium

• Sodium Chloride

• Chlorine

What makes some elements reactive?

• Oxygen – reacts with nearly every metal (example: iron rusts)

• Argon – never reacts (comes from a Greek word that means “the lazy one”)

Valence Electrons

• Determine all properties of an element (inc. reactivity)

• How do you determine number of valence electrons?

Valence Electrons

• When the highest occupied energy level (valence level) of an atom is filled with (8) electrons, the atom is stable and not likely to react.

• Atoms react in order to completely empty or completely fill their valence levels.

Ions

• An atom becomes an ion by losing or gaining electrons.

• These come from or are transferred to other atoms.

• Result is a positively- or negatively-charged particle.

Describing Ions

• Metals (left side) tend to lose electrons and become positively-charged cations.

• Non-metals (right side) tend to gain electrons and become negatively-charged anions.

Formation of Ions• Ions should gain enough

electrons to complete their valence level (max. 4) or…

• Lose enough to empty their valence level (max. 4).

• Show charge using plus/minus sign and the number of electrons lost/gained

Determine the Ionic Charge

Group Example Element Charge1A Sodium

2A Calcium

3A Aluminum

4A Carbon

5A Phosphorus

6A Oxygen

7A Iodine

8A Neon

Ionic Charges

Group Example Element Charge1A Sodium + (or 1+)

2A Calcium 2+

3A Aluminum 3+

4A Carbon 4+ or 4-

5A Phosphorus 3-

6A Oxygen 2-

7A Iodine - (or 1-)

8A Neon Never an ion!

Ionic Bonds• Cations (+) and anions

(-) are attracted to each other

• Ionic Bond – force of attraction that holds cations and anions together; forms through a transfer of electrons

Ionic Compounds• Not always in a 1-to-1 ratio!

• Subscripts are used to show that more than one atom of an element is needed

• Cation name comes first

• “-ide” added to anion name

Give the Ionic Formula

• Potassium bromide

• Sodium nitride

• Aluminum oxide

• Lithium phosphide

• Calcium sulfide

Give the Ionic Formula• Barium phosphide

• Potassium fluoride

• Aluminum sulfide

• Magnesium oxide

• Sodium bromide

• Cesium oxide

Polyatomic Ions

• Groups of atoms bonded together in a single ion with a single charge

• Often end in “–ate” or “–ite”, meaning they contain oxygen

• When writing formulas, use parentheses

Ions of Transition Metals

• Most transition metals (B groups) can take on multiple charges

• Charge given by a Roman numeral

• (Remember that metals always have POSITIVE charges!)

Write the Ionic Formula

• Copper(II) chloride

• Silver(I) oxide

• Manganese (IV) iodide

• Nickel(II) nitride

• Titanium(I) bromide

Properties of Ionic Compounds

• High melting point

• Dissolve easily

• Conduct electricity when melted or dissolved

• Crystal structure

Naming Ionic Compounds

• Names should have cation (positive) first and anion (negative) second

• Transition metals should include Roman numeral

• All compounds end in “-ide”

Name These Compounds• LiCl

• Al2S3

• CaF2

• CuBr2