COVALENT BONDING WHERE ELECTRONS ARE SHARED AND ATOMS REMAIN NEUTRAL

IONIC BONDING ELECTRONS ARE LOST BY METAL AND GAINED BY NONMETALS ATOM IS A METAL ATOM BECOMES + CHARGED -ATOM IS A NONMETAL -ATOM BECOMES --- -CHARGED

COVALENT BONDING  SHARING OF ELECTRONS  ATOMS REMAIN NEUTRAL  OCCURS BETWEEN:  2 NONMETALS  A NONMETAL AND A METALLOID  HYDROGEN AND ALL NONMETALS  PRODUCES WEAK BONDS  PRODUCES COMPOUNDS THAT HAVE LOW MELTING POINTS  ALL ORGANIC COMPOUNDS ARE COVALENT

COVALENT BONDINGBETWEEN  2 NONMETALS Nonmetals, because they have more than 4 valence electrons and especially those that have small atomic radii, will bond with them- selves in order to become stable and exist at a lower energy state. These atoms will be called DIATOMS. There are 7 diatoms That you will need to memorize. They are F, Cl, Br, I, O, N, H.

COVALENT BONDS  Between hydrogen and A nonmetal Fluorine has 7 valence electrons It needs 8 in order to exist in a lower Energy state. It could bond ionically With A metal or covalently with hydrogen by sharing one of its valence electrons. Hydrogen has only one Electron and therefore will never Lose that electron. In order for It to become stable and exist In a lower energy state, it will Share its only electron with fluorine

COVALENT BONDING BETWEEN  NONMETAL AND A METALLOID Carbon will be our only metalloid with 4 valence electrons Fluorine is a Nonmetal with 7 Valence electrons The resulting stable cmpd Contains 4 F and 1 C. Because the atoms never LOST E’s they remain neutral.

POLARITY UNEVEN DISTRIBUTION OF CHARGES Molecules tend to be asymmetric __ + On polar molecules, electrons are controlled by one Of the atoms.

Nonpolar: even distribution of charges Molecules tend to by symmetric

Water molecules are polar = the hydrogen side of the molecule ‘feels’ more positive Because of the absence electrons. The oxygen side of the molecule ‘feels’ more negative Because of the presence of electrons. Here, as in all polar molecules, oxygen has 2 energy Shells, making oxygen the ‘larger’ atom. It will control hydrogens’ electrons.

Because oxygen is controlling the electrons shared from hydrogen atoms, the electrons Will circle around oxygen’s nucleus as well as hydrogens’ nuclei. Oxygen’s greater presence of negative charges and energy, will cause the electrons to Be shared unequally=polar. + + _

Intermolecular forces: forces that hold molecules (smallest part of a covalent bond) together. In an ionic bond the opposite charges of the ions hold the compound together. In a covalent bond there are no opposite charges because electrons are not lost or gained. Hydrogen bonds: forces found between the molecules of the water molecules. H H H H H H H O O O O O O H H H H H H H

Well how does all this connect with solutions? The reason why solutes stay in solution is because of polarity. Polar solutes dissolve most easily in polar solvents – water is polar and so it can dissolve all polar molecules. Nonpolar solvents dissolve nonpolar solutes. NaCl NaCl is an ionic compound that is made up of + Na ions and - Cl ions. NaCl When an ionic compound dissolves in water it is called DISSOCIATION. Na + Cl -

If a non polar molecule is put into water, it will NOT dissolve because of the like Charges that will meet in the water and the solute. CH 4 is a symmetric molecule that is non polar. It will not dissolve in water because it will be repelled by the positive pole of the water molecule.

In the water molecule, hydrogen has the ability to form 4 bonds-two covalent with oxygen and two hydrogen bonds with oxygen of another water molecule. Because of this, cohesion, attraction between molecules of the same compound occurs. We call this kind of attractive force surface tension.

Van der Waal forces: weaker than Hydrogen bonds; found in polar molecules. Adhesion is the attractive forces acting between molecules of different substances

Solutions and suspensions: Solutions: homogenous mixture solute-substance being dissolved solvent-substance dissolving polarity H H H O O O O O H H H NaCl = Na + & Cl - Each sodium ion will dissociate (move away from) from the chlorine ion. It is still an ion so it Maintains its charge. Water is polar-hydrogen feeling more positive-oxygen feeling more neg. Ions will ‘stick’ through opposite charges to the polar ends of the water molecule=dissolving. Cl Na

Suspensions: mixture heterogeneous Blood: solution: dissolved salts, proteins, and carbohydrates suspension: blood cells and fat that are moved along but not dissolved

Acids, bases, salts, buffers Acids: forms H ions in solution. pH 1-6 Bases: form OH ions in solution pH 8-14 Salts: ionic metal and nonmetal pH 7 = neutral Buffers: weak acids and bases

Organic compounds: any compound that contains carbon and a specific ratio of hydrogen to oxygen. Because carbon has 4 valence electrons it has the capability of producing multiple bonds with not only other elements but with itself as well.

Living cells contain molecules that are Made of thousand or hundred of thousand Molecules bonded together. These molecules are called macromolecules Because they are so large.These molecules are formed through a process known as polymerization

Four macromolecules found in living cells are: Carbohydrates Lipids

Proteins: hill.com/sites/ /student_view0/cha pter2/animation__how_enzymes_work.html

Proteins: Nucleic acids:

Reactions: Dehydration: removal of water to form a compound

Glucose + glucose sucrose + water 2 monosaccharides disaccharide

Neutralization: acid + base a salt + water pH: Neutral cmpds

Activation energy-energy needed to start a reaction and produce a product. Remember= atoms bond in order to exist at a lower energy state. =every bond made contains energy =every bond broken will release energy =every compound needs a specific amount of energy to be formed

A=energy of the reactants B=activation energy C=activated complex D=energy of the products Reactants- Higher energy Products- Lower E Exothermic rxn = Spontaneous rxn

A D B C Energy of reactants is less than The energy of the products Endothermic reaction = Not spontaneous.