CHEMICAL BONDING IONIC BONDS METALLIC BONDS COVALENT BONDS HYDROGEN BONDS

IONIC BONDING When an atom of a nonmetal takes one or more electrons from an atom of a metal so both atoms end up with eight valence electrons

IONIC BONDING IS THE COMPOUND AN IONIC COMPOUND?METAL NONMETAL SUBSCRIPTS

IONIC BOND FORMATION Neutral atoms come near each other. Electron(s) are transferred from the Metal atom to the Non-metal atom. They stick together because of electrostatic forces, like magnets.

IONIC BONDING ION – any atom with more or less electrons that it is supposed to have* *Remember that the number of electrons is supposed to be equal to the number of Protons if the atom has a neutral charge

IONIC BONDING Metals will tend to lose electrons and become POSITIVE CATIONS Normal sodium atom loses one electron to become sodium ion

IONIC BONDING Nonmetals will tend to gain electrons and become NEGATIVE ANIONS Normal chlorine atom gains an electron to become a chloride ion

Na +1 is called a sodium ion The +1 symbol means it has lost one electron IONIC BONDING

Mg +2 is called a magnesium ion The +2 symbol means it has lost two electron IONIC BONDING

S -2 is called a sulfide ion The -2 symbol means it has gained two electron IONIC BONDING

Cl -1 is called a chloride ion The -1 symbol means it has gained one electron IONIC BONDING

POLYATOMIC IONS--a group of atoms that act like one ion NH ammonium ion CO carbonate ion PO phosphate ion IONIC BONDING

POLYATOMIC IONS ACT JUST LIKE ANY OTHER NEGATIVE ION WHEN BONDING IONIC BONDING

SODIUM SULFATE

IONIC BONDING

Atomic Hook-ups:Atomic Hook-ups Types of Chemical Bonds

Properties of Ionic Compounds Crystalline structure. A regular repeating arrangement of ions in the solid. Ions are strongly bonded. –Ionic Bond: the chemical bond from electrostatic attraction between positive & negative charges –EN Difference > 1.67 (see p. 266)

Crystalline structure The POSITIVE CATIONS stick to the NEGATIVE ANIONS, like a magnet.

Properties of Ionic Compounds Structure is rigid. High melting points- because of strong forces between ions.

Do they Conduct? Conducting electricity is allowing charges to move. In a solid, the ions are locked in place. Ionic solids are insulators. When melted, the ions can move around. Melted ionic compounds conduct. First get them to 800ºC. Dissolved in water they conduct.

Ionic solids are brittle

Strong Repulsion breaks crystal apart.

Section 7-2 Properties of Ionic Compounds (cont.) This figure demonstrates how and why crystals break when an external force is applied.

Metallic Bonds How atoms are held together in the solid. Metals hold onto their valence electrons very weakly. Think of them as positive ions floating in a “sea” of electrons.

Sea of Electrons Electrons are free to move through the solid. Metals conduct electricity.

Section 7-4 Metallic Bonds and the Properties of Metals (cont.) A metallic bond is the attraction of a metallic cation for delocalized electrons.metallic bond Bozeman Science – Metallic Bond

Metals are Malleable Hammered into shape (bend). Ductile - drawn into wires.

Malleable

Electrons allow atoms to slide by.

Section 7-4 Metallic Bonds and the Properties of Metals (cont.) Metals are malleable because they can be hammered into sheets. Metals are ductile because they can be drawn into wires.

Section 7-4 Metal Alloys An alloy is a mixture of elements that has metallic properties.alloy The properties of alloys differ from the elements they contain.

Section 7-4 Metal Alloys (cont.)

Section 7-4 Metal Alloys (cont.) Substitutional alloys are formed when some atoms in the original metallic solid are replaced by other metals of similar atomic structure. Interstitial alloys are formed when small holes in a metallic crystal are filled with smaller atoms.

COVALENT BONDING When an atom of one nonmetal shares one or more electrons with an atom of another nonmetal so both atoms end up with eight valence electrons

COVALENT BOND FORMATION When one nonmetal shares one or more electrons with an atom of another nonmetal so both atoms end up with eight valence electrons

COVALENT BONDING IS THE COMPOUND A COVALENT COMPOUND?NONMETAL NONMETAL YES since it is made of only nonmetal elements

Characteristics of Covalent Bonding Low Melting Point Brittle Do NOT conduct electricity

Covalent bonding Fluorine has seven valence electrons F

Covalent bonding Fluorine has seven valence electrons A second atom also has seven FF

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons FF

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons FF

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons FF

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons FF

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons FF

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons l Both end with full orbitals FF

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons l Both end with full orbitals FF 8 Valence electrons

Covalent bonding l Fluorine has seven valence electrons l A second atom also has seven l By sharing electrons l Both end with full orbitals FF 8 Valence electrons