REMEMBER! That ionic bonding happens between metal with non-metals by the transferring of electrons. Metals lose while non-metals gain the e- Results in the formation of ions ( positive and negative ions)

COVALENT BOND bond formed by the sharing of electrons There are two types of covalent bond: Polar Covalent Bond Nonpolar Covalent Bond

Covalent Bond Happens between nonmetals of similar electronegativity. Since the atoms are using (sharing) the same electrons they are stuck to each other in molecule. A molecule is a neutral particle of two or more atoms bonded to each other. Molecules may contain atoms of the same element such as N2, O2, and Cl2 or they may contain atoms of different elements like H2O, NH3, C6H12O6, CO2, or SiC.

Covalent Bonds

Molecular Compounds (covalent bond)

Covalent Bond Atoms can form single, double, and triple covalent bonds by sharing one or more pairs of electrons.

Covalent Bond When we share, sometimes we share equally (each one gets exactly half) or we can share unequally (one gets more than the other). Covalent bond is about sharing valence electrons. Sometimes the sharing is equally, sometimes one of the atoms keeps the electrons more than the other.

NONPOLAR COVALENT BONDS When electrons are shared equally the covalent bond is called Non-polar covalent. No polarity is created. H2 or Cl2 Partial charge

POLAR COVALENT BONDS Happen when electrons are shared but shared unequally. Called a polar bond because a polarity (partial charge) is created. http://www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/bom1s2_11.swf

POLAR COVALENT BONDS The electron spends more time around the F, creating a polarity, partial negative charge on the F and a partial positive charge on the H. http://www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/bom1s2_11.swf

water is a polar molecule because oxygen is more electronegative than hydrogen, and therefore electrons are pulled closer to oxygen. A simulation of polar covalent bonding in the H2O moleculehttp://web.visionlearning.com/custom/chemistry/animations/images/H2Obond.gif

Polar Covalent Bonds: Unevenly matched, but willing to share.

Polar & Non-Polar Molecules: Crash Course Chemistry https://www.youtube.com/watch?v=PVL24HAesnc A simulation of polar covalent bonding in the H2O molecule http://web.visionlearning.com/custom/chemistry/animations/CHE1.7-an-H2Obond.shtml http://www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/bom1s2_11.swf

Properties of Covalent Bonds Compared to ionic compounds, molecular compounds generally have a lower boiling point. Polar covalent bonds (like water) create intermolecular attractions. The negatively charged end attracts the positively charged end. The melting and boiling points of polar molecules is higher than that of non-polar molecules.

METALLIC BOND bond found in metals; holds metal atoms together very strongly

Metallic Bond Metallic bond is the attraction between a metal ion and the electrons surround it. Metals lose their electrons very easily. This creates positively charged metal ions and a sea of electrons around each metal ion as the valence electrons drift among the ions. Each metal ion is held together by a metallic bond. This causes metals to be good conductors at all states, be lustrous, and have very high melting points http://www.pbslearningmedia.org/asset/lsps07_int_chembonds/

Metallic Bond

You can think of metallic bond, as a Sea of Electrons. http://www.pbslearningmedia.org/asset/lsps07_int_chembonds/

Metallic Bond http://www.pbslearningmedia.org/asset/lsps07_int_chembonds/

Metallic Bonds: Mellow dogs with plenty of bones to go around.

Metals Form Alloys Metals do not combine with metals. They form an alloy which is a solution of a metal in a metal. Examples are steel, brass, bronze and pewter.

METALLIC BOND http://www.pbslearningmedia.org/asset/lsps07_int_chembonds/ Animation: http://www.drkstreet.com/resources/metallic-bonding-animation.swf http://www.pbslearningmedia.org/asset/lsps07_int_chembonds/ http://www.youtube.com/watch?v=eVv3TpaQ2-A&spfreload=10&edufilter=lXcDYxoYBxhPy6qmNJ3KKQ&safe=active

Chemical BONDS Animation: http://www.pbslearningmedia.org/asset/lsps07_int_chembonds/

Bonding Review Since the noble gases (G 18) have valence electrons they are nonreactive, or stable. Metal atoms react by losing their valence electrons. Non-metal atoms become stable when they gain or share enough electrons to have 8 valence electrons. Except H which becomes stable with 2 e. Nonmetals usually combine with metals by gaining electrons. Nonmetals can also combine with other nonmetals and metalloids by sharing electrons. Metalloids can either lose or share electrons when they combine with other elements. Hydrogen shares its electron when forming compounds with other nonmetals to obtain a stable arrangement of 2 electrons.

Do NOW What are the two types of covalent compounds? December 15 , 2015 What are the two types of covalent compounds? Compare/Contrast them!

and Molecular Compounds Properties of Ionic Compounds and Molecular Compounds

Form hard crystals with high melting points. Ionic Compounds Form hard crystals with high melting points. Conduct electric current when dissolved in water or melted. Ionic compounds form solids by building up repeating patterns of ions. The ions form an orderly, three-dimensional arrangement called a crystal.

Usually have lower melting points and boiling points. Molecular Compounds Usually do not conduct electric current when melted or dissolved in water. Usually have lower melting points and boiling points. Compared to an ionic compound, a molecular compound needs less heat to separate the molecules because the forces holding these bonds together are weaker than those of an ionic compound.

Properties of Ionic Compounds and Molecular Compounds Electric current is a flow of electrons When ionic crystals dissolve in water, the ions are free to move about, and the solution can conduct an electric current. When ionic compounds melt, the ions are free also, so they can transfer a current. Most molecular compounds do not conduct electricity because they do not contain charged particles.