Lecture 1.2 – the Octet Rule

LECTURE 1.2 – THE OCTET RULE

CA STANDARDSStudents can determine the number of

valence electrons for an element, draw a Lewis dot notation for an element and explain how the Octet rule leads to the formation of ions.

I. VALENCE SHORTCUT!• All elements in the same

group (1A, 2A, etc.) have the same number of valence electrons.

• Lewis Dot Notation shows only Valence e-

o Nitrogen (#7) = o Magnesium (#12) =o Sulfur (#16) =o Sodium

WHAT IS THE OCTET RULE?

II. THE OCTET RULE• Atoms like to have a

full outer valence shell Stable atom.

• gain or lose electrons to have an outer orbit with 8 electrons (or 2 if it is the first energy level).

• Gain/lose based on what is easiest.

III. OCTET SHORTCUT• All metals will lose

their valence electrons• All non-metals will

gain the missing ones.

WHAT ARE THE TYPES OF IONS THAT CAN FORM?

IV. IONS• When atoms gain/lose

electrons, they gain a charge.

• Ion – A charged atom due to unequal number of protons and electrons

• Cation – A positively charged ion

• Anion – A negatively charged ion

E- = DETENTION HRS. • If you gain

electrons (detention hrs.) you become negative (sad)

• If you lose electrons (detention hrs.) you become positive (happy)

CATS MAKE PEOPLE FEEL POSITIVE

CATION POSITIVE

ANION NEGATIVE

CLASS EXAMPLE• Draw dot notation for Be. Determine the

ion that forms for fluorine after the Octet Rule has been satisfied.

TABLE TALK• Draw the dot notation for Chlorine.

Determine the ion that forms for nitrogen after the Octet Rule has been satisfied.

STOP AND JOT• Draw the dot notation for Sulfur.

Determine the ion that forms for oxygen after the Octet Rule has been satisfied.

ION SHORTCUT!• All elements in the same group, form ions

with the same charge.

MOVIE