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Challenge 17

Which black rectangle is bigger?

IONIC BOND bond formed between a Metal and a Non Metal It is a transfer of electrons Metals- give up valence electrons Non –metals take in

Ionic Bonding Ionic bonding is the combining of two or more ions to form an

electrically-neutral compound

How Ionic Bonding Works

1) The giving atom loses a valence electron (or 2 or 3) so that

it has a full valence shell, but a positive charge

2) The gaining atom gains a valence electron (or 2 or 3) so

that it has a full valence shell, but a negative charge

3) The negative and positively-charged ions are attracted to

each other (like a magnet) based on their opposite charge

If you look at your periodic table, you will see that ionic

bonding usually occurs in compounds formed between one

metal and one nonmetal

Metals in Ionic Bonds In ionic bonds, metals are always the cation

-- metals are on the left side of the periodic table and only have 1, 2, or 3 valence electrons

-- it is very easy to lose these electrons and become positively charged

Nonmetals in Ionic Bonds Nonmetals (with the exception of hydrogen) are always the anion in ionic bonds

-- nonmetals all have 4 or more valence electrons, so it is very easy for them to gain electrons to get a full valence shell

-- when nonmetals gain electrons, they get a negative charge

Drawing Ionic Bonds When a nonmetal is exposed to a metal, the metal will lose electrons and the nonmetal will gain electrons, forming a new compound

-- that new compound is held together by an ionic bond

The individual atoms will have a charge, but the overall compound will be neutral

When we draw the compound, using Lewis Structures, we show the extra electron around the anion and the cation as having no valence electrons

-- each ion in the compound is shown as being charged

Example:

Na + Cl Na Cl

Ionic compounds result when metals react with nonmetals

Metals lose electrons to match the number of valence

electrons of their nearest noble gas

Positive ions form when the number of electrons are less

than the number of protons

Group 1 metals ion 1+

Group 2 metals ion 2+

Group 13 metals ion 3+

Formation of Ions from Metals

Sodium atom Sodium ion

Na – e Na +

2-8-1 2-8 ( = Ne)

11 p+ 11 p+

11 e- 10 e-

0 1+

Formation of Sodium Ion

Magnesium atom Magnesium ion

Mg – 2e Mg2+

2-8-2 2-8 (=Ne)

12 p+ 12 p+

12 e- 10 e-

0 2+

Formation of Magnesium Ion

Group 1 Group 2 Group 13

H+ Mg2+ Al3+

Li+ Ca2+

Na+ Sr2+

K+ Ba2+

Some Typical Ions with Positive Charges (Cations)

A. Number of valence electrons in aluminum

1) 1 e- 2) 2 e- 3) 3 e-

B. Change in electrons for octet

1) lose 3e- 2) gain 3 e- 3) gain 5 e-

C. Ionic charge of aluminum

1) 3- 2) 5- 3) 3+

Learning Check

A. Number of valence electrons in aluminum

3) 3 e-

B. Change in electrons for octet

1) lose 3e-

C. Ionic charge of aluminum

3) 3+

Solution

Give the ionic charge for each of the following:

A. 12 p+ and 10 e- 1) 0 2) 2+ 3) 2-

B. 50p+ and 46 e-

1) 2+ 2) 4+ 3) 4-

C. 15 p+ and 18e-

2) 3+ 2) 3- 3) 5-

Learning Check

unpaired electron octet 1 -

: F + e : F :

2-7 2-8 (= Ne) 9 p+ 9 p+ 9 e- 10 e- 0 1 - ionic charge

Fluoride Ion

In ionic compounds, nonmetals in 15, 16, and

17 gain electrons from metals

Nonmetal add electrons to achieve the octet

arrangement

Nonmetal ionic charge:

3-, 2-, or 1-

Ions from Nonmetal Ions

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 Bond

Diagram of Ionic Bonding

1). Ionic bond – electron from Na is transferred to Cl,

this causes a charge imbalance in each atom. The Na

becomes (Na+) and the Cl becomes (Cl-), charged

particles or ions.

• In an IONIC bond, electrons are given or

taken, resulting in the formation of IONS.

• The “bond” holds the atoms together and

is a result of the negative and positive ions

attracting to one another (opposites attract).

F K

What happens in an ionic bond?

F K

F K

F K

F K

F K

F K +

_

•The compound potassium fluoride

consists of a potassium (K+) ion

and a fluoride (F-) ion.

•K is positive now because it gave an

electron and F is more negative because

it took the electron.