Unit 9 Bonding Marglin Flashcard

bond
attractive force holding atoms/ions together
ionic bonds
force of attraction between oppositely charged ions
seven elements so reactive that if nothing else is around them, they will bond with themselves and form diatomic molecules
I2, Br2, Cl2, N2, O2, F2, H2
in an ionic bond, M transfers _____ to NM
1 or more electron
ionic bonds create ______ and ______
cations and anions
ionic bonds are brought together by
electrostatic attraction
ionic compound
all the ions satisfy the octet rule and all the charges cancel each other
why do bonds form?
so the atoms become more stable
exothermic
bonds forms so energy is released
endothermic
bond breaks so releases energy
ionic compounds
-made of ions
-M + NM
-neutral (charges cancel)
1st property of ionic compounds
solid at room temperature (tightly packed, vibrate in place, very organized)
2nd property of ionic compounds
crystal lattice (crystalline) structure: orderly, repeating, 3-D arrangement of atoms or ions (maximizes attractions and minimizes repulsions)
3rd property of ionic compounds
high melting points
4th property of ionic compounds
brittle
5th property of ionic compounds
soluble in water
6th property of ionic compounds
do not conduct electricity UNLESS melted (molten) or dissolved in water
ionic compounds: zinc makes a ___ charge
2+
ionic compounds: nickel makes a ___ charge
2+
ionic compound: elements in column ___ usually don’t make ions
A4
Lewis Dot Diagrams
Gilbert Lewis devised a way to easily visualize bonding.
how to do lewis dot diagrams
use the chemical symbol to represent the nucleus and the inner core electrons. Use dots to represent the valence electrons
monatomic ions
made from one atom
polyatomic ions
made from groups of atoms that are covalently bonded together (and so act as a unit)
how to name ionic compounds
-name the cation
-name the anion
how to name monatomic cations
say/write the name of the element, followed by the word ion.
TM can make _______ ion charge, so we signify their charges by using a _________ in parentheses
more than 1, roman numeral. [Fe^2+ is iron (II) ion, Fe^3+ is iron (III) ion]
monatomic cation exceptions (no roman numeral)
zinc, silver, cadmium, nickel
monatomic cation exceptions (need roman numerals)
tin, lead [Pb^2+ is lead(II)ion] [Sn^4+ is tin(IV)ion]
monatomic anions: change the ending of the name to ____
“ide”
polyatomic ions characteristics
-most are anions
-most contain O atoms
-most end in “ate” or “ite”
-ate ions have ___ more O atom than -ite atoms
1
ammonium
NH4^1+
cyanide
CN^1-
hydroxide
OH^1-
carbonate
CO3^2-
nitrate
NO3^1-
phosphate
PO4^3-
sulfate
SO4^2-
carbonite
CO2^2-
nitrite
NO2^1-
phosphite
PO3^3-
sulfite
SO3^2-
per–ate
XO4^1-
-ate
XO3^1-
-ite
XO2^1-
hypo–ite
XO^1-
bicarbonate
HCO3^1-
acetate
C2H3O2^1-
dichromate
Cr2O7^2-
chromate
CrO4^2-
oxalate
C2O4^2-
permanganate
MnO4^1-
CaCO3
calcium carbonate
Ba(OH)2
barium hydroxide
how to name an ionic compound
-name the cation
-name the anion
binary
contains two elements
ternary
contains 3 elements
how to make an ionic compound formula
-write the symbol and charge for each ion
-“drop and swap” the charges (just the #, not the signs) to get the subscripts
-reduce if necessary
-use parentheses if you need a subscript for a polyatomic atom
aluminum sulfate
Al2(SO4)3
iron(II)hydroxide
Fe(OH)2
chemical formula
tells you the number and kinds of atoms in the compound
formula unit
the smallest piece of an ionic compound that is neutral (f.u.)
empirical formula
the lowest whole number ratio of atoms (or ions) in the compounds, the EF is ALWAYS the correct formula
barium oxalate
BaC2O4
lithium chlorate
LiClO3
Pb(SO4)2
lead(IV)sulfate
Cd(CLO2)2
cadmium chlorite
3 ways to recognize molecular compounds
-contain atoms (neutral)
-nonmetal elements(ONLY)
-have covalent bonds(formed by sharing electrons)
3 ways to recognize ionic compounds
-starts with a metal
-has parentheses
-contains polyatomic ion
valence electrons are _____ to the nucleus of another atom (and vice-versa)
attracted
single bond
one shared pair of electrons
double bond
two shared pairs of electrons
triple bond
three shared pairs of electrons
properties of molecular coumpounds
-wide variety of properties (too many to categorize all molecular compounds)
examples of properties of molecular compounds
-some are solid, some are liquid, some are gases
-some have a crystalline structure, a few do not
-some have high melting points, others don’t
-some are soluble in water, some are not
-almost none can conduct electricity (nonelectrolytes)
molecule
the smallest piece of a molecular chomping that had the same properties as the compound
molecular compound names have __________
numerical prefixes
how to name a molecular compound
-name each element;change the ending of the 2nd element to “ide”
-change the subscripts into prefixes
-do not use mono for the 1st element
-drop the ending vowel of the prefix if the element name starts with “o”
SF2
sulfur difluorite
N2O
dinitrogen monoxide
C3H3
tricarbon octahydride
NH3
nitrogen trihydride
how to write the formula for a molecular compound
-change the element names to their symbols
-change the prefixes to subscripts
iodine trichloride
ICl3
tetraphosphorous decoxide
P4O10
chemical formula
shows you number and kinds of atoms in the compound
molecular formula
tells the number and kind of atoms in the molecule
structural formula
shows which atoms are attached (and how)
steps 1-2 to draw Lewis structures
•count up all the valence electrons in the species
•draw a skeleton structure
-the least electronegative element usually is the 1st in the chemical formula & is often the central atom
-H (& most of the time halogens) are terminal atoms (“ends” of molecules) because they only make one bond
-molecules tend to be compact & symmetrical, rather than long, stringy thingies
steps 3-6 to draw Lewis Structures
•subtract 2 electrons for each bond you drew
•try to arrange the remaining electrons to satisfy the octet rule for all the atoms
•if you need more electrons than you have, draw a double (or triple) bond, subtract 2electrons and try again
•if you have more electrons than you need, place u shared pair(s) on the central atom (expanded octet)
elements most likely to make multiple bonds
C, O, N, S
resonance
when a molecule (or ion)can have MORE THAN 1 correct Lewis Structure and the ONLY difference if the arrangement of the electrons (not the atoms)
Resonance Hybrid
blends those multiple structures together
coordinate covalent bond
formed when one atoms contributes both electrons to shared pair
1st exception to octet rule
central atom has less than 8 valence electrons. occurs if central atom has less than 4 valence electrons by itself
2nd exception to octet rule
central atom has less than 8 valence electrons(expanded octet). occurs only if the central atoms had empty d orbitals to promote electrons into (i.e. only with elements in columns 5A, 6A, 7A, or 8A on Pd. 3 or lower in the Pd.T)
3rd exception to octet rule
molecule has an odd # of valence electrons
unpaired electrons in a molecule make it highly reactive. these species are called __________
free radicals
electronegativity
some atoms are better able to attract electrons than others
difference in electronegativity
determined bond polarity
dipole
bond or molecule that has 2 ends with slightly opposite charges
0.5-1.9 difference in electronegativity
polar
0-0.4 difference in electronegativity
nonpolar
2.0+ difference in electronegativity
ionic
2 ways to signify polar bonds
•arrows +—->
•deltas (+/-)
bond (dissociation) energy
the amount of energy required to break a bond
“big” atoms have ____ bond lengths than “small” atoms
longer
bond energy ______ as bond length ______
increases, decreases
bond lenghts
single > double > triple
polar bonds have ______ energies than nonpolar bonds
higher
acids
special case of molecular compounds
acid characteristics
-made of all nonmetal atoms
-dissolve in (actually, hey react with) H2O to make H^+ ions
-acids are named after their anions
ion ending: -ate
acid: -ic
ion ending: -ite
acid: -ous
ion ending: -ide
acid: hydro-ic
how to name an acid
-identify the anion and change the ending appropriately
-write “acid” at the end
HClO4
perchlorate acid
HClO3
chloric acid
HClO2
chlorous acid
HClO
hypochlorous acid
HCl
hypochloric acid
how to write an acid formula
-change “acid” to “H”
-identify the anion(by the acid name)
-may need to drop & swap
sulfuric acid
H2SO4
phosphorous acid
H3PO3
hydrates
-special case of ionic compounds
-ionic crystals can trap water molecules b/w the ions
-hydrates tend to be colored compounds
-when heated, the ionic compound stays solid but the water is evaporated and the compound loses its color
anhydrous form
when is heated, the hydrate stays solid, but the water is driven off(evaporated) so the compound loses its color
how to name a hydrate
-name the ionic compound
-use the numerical prefix; write hydrate
CuSO4•5H2O
Copper(II)Sulfate Pentahydrate
CuCl2•2H2O
Copper(II)Chloride Dihydrate

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