Chemistry

Why do carbon atoms always share four electron pairs in chemical compounds?

Carbon atoms have four valence electrons, so they need four more electrons from other atoms to satisfy the octet rule. each covalent bond adds one electron to the valence shell of carbon, so carbon must from four covalent bonds.

Explain why carbon is uniquely suited to be the main structural element of organic chemistry, and describe the ways in which carbon atoms form covalent bonds.

-Carbon atoms normally share four pairs of electrons when they form compounds -Carbon can form single, double, and triple bonds -when a carbon atom forms four single bonds, the bonds form a tetrahedral arrangement -hydrogen atoms normally share one pair of electrons when they form compounds

Understand how and why chemists use functional groups to classify organic molecules

-a functional group is any bond or atom that is not found in a saturated hydrocarbon -a functional group includes all of the atoms and bonds that give a molecule its characteristic chemical properties -compounds that contain the same functional group typically undergo the same types of reactions -organic retains normally affect the functional group without changing the carbon skeleton of a molecule

Learn the names of the first 10 linear alkanes, and use common conventions to draw their structural formulas

-alkanes are hydrocarbons that contain only single bonds, and linear alkanes contain a single continuous chain of carbon atoms -linear alkanes can be represented using lewis dot structures, full structural formulas, condensed structural formulas, line structures, or wedge-dash structures

Name and draw the structures of linear alkenes and alkynes and describe how the atoms are arranged around a double or triple bond

-alkenes and alkynes are hydrocarbons that contain a double or triple bond, respectively -the bonds around the two carbon atoms that make up an alkene group form a trigonal planar arrangement -the bonds around the two carbon atoms that make up an alkene group are arranged in a straight line -the IUPAC system names alkenes and alkynes by identifying the corresponding alkane, changing the ending of the alkane name to a suffix that identifies the functional group, and adding a number to show the location of the double bond -cycloalkenes contain a carbon-carbon double bond within a ring a croon atoms

draw the structure of benzene and recognize the benzene structure in aromatic compounds

-benzene is a six-memebered ring of carbon atoms with alternating single and double bonds. two or the electrons that make up each double bond are free to move around the entire ring -aromatic compounds contain one or more benzene ring -aromatic hydrocarbons are less reactive than alkenes

Describe how the physical properties of hydrocarbons are related to their structures, and write the chemical equation for the combustion reaction of hydrocarbon

-hydrocarbons are typically easy to melt and boil, are less dense than water, and have very low solubilities in water -the melting and boiling points of hydrocarbons depend on the number of carbon atoms. melting points also depend on the shape of the carbon skeleton, but the presence of double and triple bonds usually has a limited impact on physical properties -hydrocarbons react with oxygen to form carbon dioxide and water -combustion reactions produce large amounts of energy, and they are the primary energy source for modern society

distinguish linear and breached alkanes and cycloalkanes, and recognize and draw isomers of simple alkanes

-isomers are molecules that have the same molecular formula but different structures and they normally have different physical and chemical properties -constitutional isomers differ in the order in which atoms are connected to one another -branched alkanes contain a branched chain of carbon atoms -cycloalkanes contain a ring of carbon atoms

name and draw the ci and trans forms of an alkene and distinguish constitutional isomers and stereoisomers

-molecules that have the same molecular formula but differ in the arrangement of bonds around a carbon atom are called stereoisomers -alkenes that have an internal double bond can occur in cis and trans forms, which are exempts of stereoisomers

Name branched alkanes and cycloalkanes

-the IUPAC system provides a systematic way to name branched alkanes, by identifying the principal carbon chain, the individual branches, and the location of the branches on the principal chain -The IUPAC rules can be used to name branched cycloalkanes

What is a tetrahedral arrangement? give an example of a compound that had this arrangement of atoms?

A tetrahedral arrangement is a triangular triangular pyramid of atoms surrounding a central atom. CH4 has this arrangement.

Why is CH3 not correct?

Carbon atoms must form four bonds to satisfy the octet rule. in this structure, carbon only forms three bonds, so this is not a stable molecule.