Chemistry ReviewChemistry Review

Review ConceptsReview Concepts

AtomAtom: smallest unit of matter that maintains : smallest unit of matter that maintains ALL of the properties of an elementALL of the properties of an element

Proton, Neutron, ElectronProton, Neutron, Electron: (+), (0), (-): (+), (0), (-) ElementElement: substance that cannot chemically : substance that cannot chemically

be broken down any furtherbe broken down any further CompoundCompound: two or more elements combined: two or more elements combined MatterMatter: has mass and takes up space: has mass and takes up space

The SpecificsThe Specifics

ProtonsProtons and and NeutronsNeutrons are located in the are located in the atomic nucleus together.atomic nucleus together.

ElectronsElectrons are found in the outer valence are found in the outer valence shells of the atom.shells of the atom.

Atomic massAtomic mass is measured in daltons: is measured in daltons:– 1 proton/neutron = 1 1 proton/neutron = 1 daltondalton = 1 = 1 amuamu– Equal to 0.0000000000000000000000017gEqual to 0.0000000000000000000000017g

Electrons are not counted as part of the Electrons are not counted as part of the atomic mass b/c they are 1/2000 of 1 amu.atomic mass b/c they are 1/2000 of 1 amu.

In the HUMAN BODYIn the HUMAN BODY

96% of the body is made up of 4 elements:96% of the body is made up of 4 elements:– Carbon, Hydrogen, Oxygen, & NitrogenCarbon, Hydrogen, Oxygen, & Nitrogen

The remaining 4 percent is composed of The remaining 4 percent is composed of several important elements:several important elements:– P, Ca, K, S, Na, Cl, Mg P, Ca, K, S, Na, Cl, Mg – Several trace elements Several trace elements

concentration less than 0.01 %- Fe, Cu, F, I, Snconcentration less than 0.01 %- Fe, Cu, F, I, Sn

Reading the Periodic TableReading the Periodic Table

25

Mn

54.9380

Atomic number

Atomic Weight

Tells number of protons in the nucleus

Mass in the nucleus

IsotopesIsotopes

All atoms of the same element contain the All atoms of the same element contain the same number of protonssame number of protons

**Some atoms have a greater number of **Some atoms have a greater number of neutrons and therefore have a greater neutrons and therefore have a greater atomic weight– these are isotopes**atomic weight– these are isotopes**

Most common isotope = carbonMost common isotope = carbon– Carbon 12, Carbon 13, and Carbon 12, Carbon 13, and Carbon 14Carbon 14– All have 6 protons, but different number of All have 6 protons, but different number of

neutronsneutrons

OrbitalsOrbitals

Orbitals are 3D spaces in which electrons Orbitals are 3D spaces in which electrons are foundare found

s, p, d, and f orbitals exists, p, d, and f orbitals exist No more than 2 electrons can be in the No more than 2 electrons can be in the

same orbitalsame orbital 1s and 2s orbital are both circular1s and 2s orbital are both circular 2p orbital is dumbell shaped with X, Y, and 2p orbital is dumbell shaped with X, Y, and

Z planeZ plane

Remember:Remember:

The elements on the far right of the periodic The elements on the far right of the periodic table are generally “unreactive”.table are generally “unreactive”.

Unpaired electrons are the reason for Unpaired electrons are the reason for chemical reactionschemical reactions

Covalent bonds and Ionic bonds are the Covalent bonds and Ionic bonds are the strongest chemical bonds.strongest chemical bonds.

Covalent BondsCovalent Bonds

Occurs when electrons are shared between Occurs when electrons are shared between two or more elementstwo or more elements

When 1 electron is shared a single covalent When 1 electron is shared a single covalent bond is formedbond is formed

When 2 electrons are shared between When 2 electrons are shared between elements a double covalent bond is formed.elements a double covalent bond is formed.

Compounds and MoleculesCompounds and Molecules

Molecules are formed between 2 atoms of Molecules are formed between 2 atoms of the same elementthe same element

O2 or H2O2 or H2

Compounds are formed between two or Compounds are formed between two or more elementsmore elements

H2OH2O

ElectronegativityElectronegativity

Defined as the attraction for a covalent bondDefined as the attraction for a covalent bond

Non-polar covalent bonds are formed Non-polar covalent bonds are formed between elements that have the same between elements that have the same electronegativityelectronegativity

Polar covalent bonds are formed when one Polar covalent bonds are formed when one atom in the bond has a higher atom in the bond has a higher electronegativity. electronegativity.

Ionic bondsIonic bonds

Typically form when an electron is pulled Typically form when an electron is pulled away from an element by another elementaway from an element by another element

Cation- positive charged atomCation- positive charged atom Anion- negative charged atomAnion- negative charged atom Ionic bonds are very dependent on the Ionic bonds are very dependent on the

environment to form and stay togetherenvironment to form and stay together– Temperature, humidity, exposure to other elementsTemperature, humidity, exposure to other elements

Weaker InteractionsWeaker Interactions

Other bonds exist in chemical interactionOther bonds exist in chemical interaction H bondsH bonds Van der Waals forcesVan der Waals forces

All very influential in biological chemistryAll very influential in biological chemistry Influences shape, structure, and formation Influences shape, structure, and formation

of specific molecules (proteins)of specific molecules (proteins)

Hydroxyl GroupHydroxyl Group

Hydrogen atom is bonded to an oxygen Hydrogen atom is bonded to an oxygen atomatom

AlcoholsAlcohols Water molecules are attracted to the Water molecules are attracted to the

hydroxyl group because of polarityhydroxyl group because of polarity

Carbonyl GroupCarbonyl Group

Carbon atom double bonded to the oxygen Carbon atom double bonded to the oxygen atoms with one hydrogenatoms with one hydrogen

Aldehyde:Aldehyde:– Attached to a multiple carbon chain groupAttached to a multiple carbon chain group

Ketone: Ketone: – Attached to any other groupAttached to any other group

Carboxyl GroupCarboxyl Group

Double bond of oxygen to carbon atoms that Double bond of oxygen to carbon atoms that is then bonded to a hydroxyl groupis then bonded to a hydroxyl group

When the –OH group disassociates it When the –OH group disassociates it creates Hcreates H++ ions ions

This groups makes organic acidsThis groups makes organic acids

Amino GroupAmino Group

Made of a nitrogen atom bonded to two Made of a nitrogen atom bonded to two hydrogen atoms and the carbon R grouphydrogen atoms and the carbon R group

Most common in biological systems as the Most common in biological systems as the ionized form = NH3ionized form = NH3++

Combined with the carboxyl groups makes Combined with the carboxyl groups makes amino acids (Proteins@!)amino acids (Proteins@!)

Sulfhydryl GroupSulfhydryl Group

Made of sulfur atom bonding to a hydrogen Made of sulfur atom bonding to a hydrogen atomatom

Resembles the OH groupResembles the OH group

Also involved with production of proteinsAlso involved with production of proteins

Phosphate GroupPhosphate Group

Carbon skeleton with an Oxygen atom at Carbon skeleton with an Oxygen atom at one end is bonded to a Phosphorus atom one end is bonded to a Phosphorus atom and 3 more oxygen atoms and 3 more oxygen atoms

IsomersIsomers

IsomersIsomers are molecules that have the same are molecules that have the same chemical formula but different arrangements of the chemical formula but different arrangements of the atoms.atoms.

Structural isomers differ in terms of how atoms are Structural isomers differ in terms of how atoms are joined together.joined together.

Optical isomers are mirror images of each other.Optical isomers are mirror images of each other. Optical isomers can occur whenever a carbon has Optical isomers can occur whenever a carbon has

four different atoms or groups attached to it. four different atoms or groups attached to it.

IsomersIsomers