Chem Final Review Chapters 1

• number of protons in the nucleus
• usually similar to the number of protons, but can vary. 
• atms with the same number of protons but different numbers of neurons

• electrons
• waves 
• particles
• orbitals

we can bever really know exactly where the electron is; but we can determine the electron density (the probability of finding an electron ina  particular part of the orbital)

• shells
• principal quantum number 
• n=1 
• the shells are farther from the nucleus, higher in energy, and can hold more electrons

• flat (planar) region of space, including the nucleus, with zero electron density
• degenerate orbitals
• each orbital can hold a max of two electrons, provided their spins are paired

• those in the outermost shell
• carbon=4
• nitrogen=5
• oxygen= 6

when there are two or more orbitals of the same energy, electrons will go into different orbitals rather than pair up in the same orbital

ionic bonding: transfer of electrons, resulting in large crystal lattice

covalent bonding: shared electrons not transferred

valence-shell electrons that are not shared between two atoms

lone pair

as a guide in predicting whether a given bond will be polar and the direction of its dipole moment

increases from left to right and from bottom to top

FC= [group number]- [nonbonding e]-[number of bonds (or 1/2 the number of shared electrons)]

• ionic bonds
• covalent bonds
• having a chloride ion bonded, not a covalent bond to chloride

- charge delocalization (the positive on the less EN and hte negative on the more EN)

• a single double-headed arrow
• two single headed arrows in opposite directions
• oscillate back and forth; they are delocalized over all the resonance forms at the same time

True

no; there are major and minor contributors, depending on the most stable

the major is the one with the lowest energy, generally having all octets satisfied, as many bonds as possible, and as little charge separation as possible; negative charges are on the more EN, like O, N, and S

• lewis structures 
• condensed structural formulas

line angle formula

the number of atoms of each element (ex: C2H2)

• two step process:
• - first, determine the empirical formula, simply the relative ratios of the elements present
• - divide the MW of the sample by the empirical weight

• 1) assume the sample contains 100g so the percent value gives the number of grams. Divide that number of grams by the atomic weight to get the number of moles. 
• 2) Divie each of the number of moles by the smallest one.

• acid: substances htat dissociate in water to give hydronium ions
• bases: substances that dissociate in water to give hydroxide ions

the pH and hte acidity in logarithms (neutral is 7)

• acid: any species that can donate a proton
• base: any species that can accept a proton

• BL bases do not have to have hydroxides 
• Arrhenius bases must have OH

conjugate acid= when a base accepts a proton, it becoems an acid capable of returning that proton

conjugate base= when an acid donates a proton, it becomes a base capable of accepting that proton

the acid-dissociation constant and its value indicates the relative strength of the acid; the stronger the acid, the more it dissociates, giving a larger value of Ka

strong acids: around 0 or negative

weak acids: around four

inversely related to the strength of its conjugate base

its conjugate base must be stable in its anionic form; otherwise, HA would not easily lose its proton. Therefore, the conjugate base of a strong acid must be a weak base. On the other hand, if an acid is weak, its conjugate base is a strong base

• HCl
• H3O+
• HF
• H-COOH
• CH3COOH
• HCN
• NH4

• -CH3 (methyl anion)
• NH2- (amide ion)
• CH3CH2O-
• HO-
• NH3

the weaker acid and base

• The stronger an acid, the weaker its conjugate base
• the weaker an acid, the stronger its conjugate base
• acid-base reactions favor the weaker acid and the weaker base

a more electronegative element bears a negative charge more easily, giving a more stable conjugate base and a stronger acid; increases from left to right

• EN
• C < N < O < F

the negative charge of an anion is more stable if spread over a larger region of space; acidity increases down the colum as the size of the element increases

• Acidity: HF < HCl <HBr < HI
• Stability F- < Cl- < Br- < I-

• the dominant
• ethoxide
• because acids are stronger if theey lose a proton give resonance-stabilized conjugate bases. Therefore, if there is no resonance possible, the base will be strong and the acid will be weak

• sigma bond
• inductive effect

the number of bonds between the EN element and the site of hte negative charge

the acidity increases by adding a chlorine, and the effect is larger if the chlorine atom is closer to the acidic group

• acids: species that can accept these electron pairs to form new bonds (accepts a pair of electrons; electrophile)
• base: species with available electrons that can be donated to form new bonds (donates a pair of electrons (nucleophile))