UNIT 5 CHEMICAL BONDINGChapter 6.1 Lewis Dot Diagrams & Ions

STABLE ELECTRON CONFIGURATIONS

When is an atom unlikely to react?When the outer shell (highest occupied

energy level) is ________ with electrons ____ e- for Octet Rule

Noble gases are the most ______ elements.The highest occupied energy level is

completely filled. Elements tend to _______ to achieve

electron configurations similar to those of noble gases.

STABLE ELECTRON CONFIGURATIONS

___________ properties of an element depend on the number of valence electrons.

Electron dot diagram - [___________ _________] is alternative to standard electron shell diagramDot diagram emphasizes valence

electrons (inner shells hidden)

ELECTRON CONFIGURATION AND LEWIS DOT DIAGRAMS

Lewis Dot Diagram

Both of these mean the same thing

LEWIS DOT DIAGRAM

Element symbol represents:____________

ANDAll ________ core electrons

Dots represent: ___________ electrons (outer shell –

Highest occupied energy level)

F

STABLE ELECTRON CONFIGURATIONS – LEWIS DOT DIAGRAMS

FORMATION OF IONS

When an atom _______ or ________ an electron(s) atom is no longer neutral. # of Protons NO LONGER EQUAL # of

electrons

Definition: ION = _______ (or group of atoms) with

positive (+) or negative (-) net ________ charge.

FORMATION OF IONS ANION = Ion with a ______________ (-) charge

[Memory aid: anion = A Negative ION]

Example: Chlorineatomic # 17Halogen Family/Group 7A

7 Valence ElectronsNeutral (but not stable) - 17 protons and 17

electronsTo become stable – ______ 1 electron in outer e-

shell Now have 1 more e- than proton = -1 net charge

Symbol is written ______ or _______

FORMATION OF IONS

Naming Anions:Part of element name + suffix “______”

Example: Chlorine ion becomes “chlor” + “ide”

Cl- is called a chloride ion F- is the ___________ ion Br- is the ___________ ion I- is the ______________ ion

FORMATION OF IONS

CATION = Ion with a _____________ charge

Example: Sodium atomic # 11Alkali Metal Family/Group 1A

1 Valence Electron Neutral (but not stable) -11 protons and 11 electronsTo become stable – _______ the 1 electron in outer e-

shell Now has 1 more proton than electron = 1+ net charge

Symbol is written ______ or ______

FORMATION OF IONS

Naming ___________:Use the normal element name

Na+ is called a sodium ion Li+ is the __________ ionCs+ is the __________ ionFr+ is the __________ ion

BONDING

Elements achieve stable electron configurations by _____________ or ___________ electrons between atoms

Transferring Electrons -Those with ___ valence electrons “_____”

themThese elements “lose” valence electrons

OR

Those with ____ valence electrons “_________” themThese elements “gain” electrons

FORMATION OF IONS & BONDING

Sodium reacts with chlorine electron transferred from sodium to

chlorine

Each atom ends up more stable

IONIC BONDING

Chemical bond = ________ that holds atoms or ions together as a unit.

Opposites ________Particle(s) with negative charge attracts

particle(s) with positive charge.

Ionic bond • Force that holds cations and anions together and

which involves the _____________ of electrons. • Bond occurs between a ________ and a nonmetal

IONIC BONDING Ionic Compounds

What is the chemical formula for magnesium chloride? Mg and Cl

First determine the Lewis Dot Diagram and Ions for each element:

Ions Lewis Dot

IONIC BONDING

Mg atom cannot reach a ________ electron configuration by giving up just 1 valence electron or __________ with just 1 chlorine atom.

IONIC BONDING

Mg transfers ___ electrons, one to each of the ____ Cl atoms.

After transfer Charge on the magnesium ion is 2+

Charge on the 2 chloride ions is 1-

IONIC BONDING

Formula for magnesium chloride is MgCl2

PROPERTIES OF IONIC COMPOUNDS

The properties of sodium chloride are typical of ________ compounds.________ melting point

sodium chloride melts ~800°CWhen solid - ______ conductor of

electric currentWhen liquid (melted) - _______

conductor of electric current. Brittle - crystals shatter when struck

with a mallet