Ionic and Covalent Bonding

What We Know:Valance Electrons

Valance electrons are the electrons in the highest energy level (outermost shell)1

2 3 4 5 6 7

8

What We Know:Lewis Dot

Shows the valance electrons available for bonding

All want to be at lowest energy level (full 8 or lose e–)

What We Know:Bonding

Atoms bond with other atoms by transferring or sharing electrons.

Are We Comfortable?

Fist to five, how comfortable are you with the two topics I have just shown:

Valance ElectronsLewis Dot

Adding a New Terms

Electronegativity: the measure of an atom’s ability to attract electrons to itself (In other words: how badly an atom want’s to “hug” or “keep” it’s electrons)

Adding New Terms

Electron Affinity: the measure of an atom’s ability to attract extra electrons (In other words, how badly an atom “wants” another electron)

Adding New Terms

Ion: an atom whose total number of electrons does not equal the total number of protons (In other words, it has more or less electrons than it should have)

This mostly happens when a chemical reaction(breaking and forming of bonds) occurs

Let’s Look At An Example:

Cl

K

Low electronegativity

Low electron affinity

High electronegativity

High electron affinity

Potassium wants to LOSE and Chlorine wants to GAIN

Let’s Look At An Example:

Cl

K

Low electronegativity

Low electron affinity

High electronegativity

High electron affinity

Potassium wants to LOSE and Chlorine wants to GAIN

Let’s Look At An Example:

Cl

K

Becomes a positive ion (because lost a negatively charged electron)

Becomes a negative ion (because gained a negatively charged electron)

+–

Let’s Look At An Example:

Cl

K+ –

Ionic BondsIonic Bond: when one atom TRANSFERS it’s electrons to another atom (an uneven “sharing” of electrons)

Cl

K+ –

OHH

+

+

–

Ionic BondsIonic Bond: when one atom TRANSFERS it’s electrons to another atom (an uneven “sharing” of electrons)

Occurs between metals and non-metals

Creates an ionic compound Cl

K+ –

OHH

+

+

–

You Try!Draw the Lewis Dot Structure for each of the following ionic bonds.

Then label which has a high electronegativity (and which has a low), and which has a high electron affinity (and which has a low).

Then draw the ionic compound, labeling which atom is becomes a negative ion, and which becomes a positive ion when they bond

Li + F K + Br Na + I

Adding New Terms

Covalent Bonds: when atoms share electrons (evenly)

This occurs when non-metals and non-metals bond

Creates covalent compounds

Let’s Look At An Example:

FFHigh electronegativity

High electron affinity

High electronegativity

High electron affinity

Both Fluorine’s want to GAINThey EQUALLY want that electron…so they

SHARE

Let’s Look At An Example

F F

You Try!Determine which of the following will create ionic bonds and which will create covalent bonds – JUST BY LOOKING AT THEIR PLACE ON THE PERIODIC TABLE:

N + NNa + BrMg + OC + O + O (CO2)

You Try!Determine which of the following will create ionic bonds and which will create covalent bonds – JUST BY LOOKING AT THEIR PLACE ON THE PERIODIC TABLE:

N + NNa + BrMg + OC + O + O (CO2)

Covalent

Ionic

Ionic

Covalent

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