bonding and nomenclature II Flashcards
what are acids?
ionic compounds that contain H^+1 as their cation
how are acids named?
based on their anion
how is an anion named if it ends in -ide?
hydro__ic acid (the root name of the anion goes in the space)
how is an anion named if it ends in -ate?
__ic acid
how is an anion named if it ends in -ite?
__ous acid
mnemonic devices to remember -ate and -ite endings:
i “ate” something “ic”ky
gingiv”ite”“ous”
prefixes for molecular compounds:
1 - mono 2 - di 3 - tri 4 - tetra 5 - penta 6 - hexa 7 - hepta 8 - octa 9 - nona 10 - deca
what are the rules for naming molecular compounds?
- use the prefixes to indicate how many of each element is in one molecule
- change the ending on the second element to “-ide”
- if there’s only one of the first element, do not write “mono” in front of it
where will atoms in a molecule try to orient themselves? why?
as far as possible due to electron density in the bond repelling other electron-dense areas
what does VSEPR stand for? what does it mean? what does it cause?
valence shell electron pair repulsion. it means that paired valence electrons push away from each other. it causes the 3D structure of molecules
what is VSEPR based on?
the total number of electron domains around the central atom
what is an electron domain?
the area where electron pairs are most likely to be found
in what form do pairs of electrons come?
single bond, multiple bond, or nonbonding pair
describe all configurations and aspects of configurations with 2 electron domains:
domain geometry: linear bonding pairs: 2 nonbonding pairs: 0 molecular geometry: linear bond angle: 180º
describe all configurations and aspects of configurations with 3 electron domains:
domain geometry: trigonal planar bonding pairs: 3 nonbonding pairs: 0 molecular geometry: trigonal planar bond angle: 120º
domain geometry: trigonal planar bonding pairs: 2 nonbonding pairs: 1 molecular geometry: bent bond angle: <120º
describe all configurations and aspects of configurations with 4 electron domains:
shape: tetrahedral bonding pairs: 4 nonbonding pairs: 0 molecular geometry: tetrahedral bond angle: 109.5º
shape: tetrahedral bonding pairs: 3 nonbonding pairs: 1 molecular geometry: trigonal pyramidal bond angle: <109.5º
shape: tetrahedral bonding pairs: 2 nonbonding pairs: 1 molecular geometry: bent bond angle: <109.5º
describe all configurations and aspects of configurations with five electron domains:
5 and onward break the octet rule
shape: trigonal bipyramidal bonding pairs: 5 nonbonding pairs: 0 molecular geometry: trigonal bipyramidal bond angles: 120º, 90º (120 between the arms, 90 between the branches)
shape: trigonal bipyramidal bonding pairs: 4 nonbonding pairs: 1 molecular geometry: seesaw bonding angles: 120º, 90º
shape: trigonal bipyramidal bonding pairs: 3 nonbonding pairs: 2 molecular geometry: t-shaped bonding angles: 120º, 90º
shape: trigonal bipyramidal bonding pairs: 2 nonbonding pairs: 3 molecular geometry: linear bonding angle: 180º
what parts of a molecule with five electron domains become its nonbonding pairs?
its three lobes
describe all configurations and aspects of configurations with 6 electron domains
shape: octahedral bonding pairs: 6 nonbonding pairs: 0 molecular geometry: octahedral bond angle: 90º
shape: octahedral bonding pairs: 5 nonbonding pairs: 1 molecular geometry: square pyramidal bond angle: 90º
shape: octahedral bonding pairs: 4 nonbonding pairs: 2 molecular geometry: square planar bond angle: 90º
shape: octahedral bonding pairs: 3 nonbonding pairs: 3 molecular geometry: t-shaped bonding angles: 120º, 90º
what parts of a molecule with six electron domains become its nonbonding pairs first?
the polars (top and bottom)
when is the only time we deal with 5 and 6 domains for central atoms?
when they are able to obtain more than an octet
when is the only time we deal with 5 and 6 domains for central atoms?
when they are able to obtain more than an octet
how many poles may bonds have? what does it depend on?
2, their electronegativites
what is a polar bond?
bonds where the electrons are shared unequally between atoms
which atom in a polar bond pulls the electron closer to itself?
the more electronegative atom
what is the electronegativity difference between atoms in a polar covalent bond?
0.5-1.7, but it can be higher than 1.7
what does it mean in terms of polarity when atoms are different?
it means that each atom has a different pull on the electrons
what is a nonpolar bond?
when electrons are shared equally between two atoms
what constitutes a nonpolar bond?
when atoms that are the same have the same pull on the shared electrons (same electronegativity values) or have an electronegativity difference between 0-0.4
what are the general rules to determining if a molecule is polar or nonpolar?
- different atoms around a central atom will always be polar molecules
- same atoms around a central atom are always nonpolar molecules
how should you picture unshared electrons/lone pairs when it comes to polarity?
picture them as a different atom, making the bond polar regardless of if the central atom is surrounded by the same atoms (eg H2O)
what does molecular polarity depend on?
- bond polarity
2. the shape of the molecule (symmetrical versus asymmetrical)
what is a network solid?
when many atoms are bonded together to make a large crystal
what is a network solid referred to as?
a macromolecule
what is the structure of a macromolecule?
extremely rigid
describe the properties of a network solid/macromolecule. why does it have these properties?
very strong crystal, very high boiling point/melting point. not due to the type of bond (covalent), but because of how many bonds are present
what are examples of network solids?
pure c (diamond), SiC (coating for very hard tools), graphite, SiO2 (quartz)
what do metals not do well? what does this lead to when metal atoms are bonded together?
metals don’t hold electrons very well, leading to electrons moving between valence shells when metals are bonded and not staying around any particular atoms (they instead “float” from atom to atom)
what is it called when in a metallic bond electrons move between valence shells, “floating” from atom to atom?
the “sea of mobile electrons”
what properties does mobility give to metals?
malleability, conductivity, and luster
what is a metallic bond
metal + metal
what is an alloy?
different metal atoms bonded together
what is brass?
copper + zinc
what is an ionic bond made of? what are its properties with regards to the periodic table, electronegativity, and ionic character?
metal + nonmetal, further apart on the periodic table, greater difference in electronegativity, higher ionic character
which elements have high ionic characters? which have higher ionic characters?
Cr, P = high ionic character
Cl, Ca = higher ionic character
what is a covalent bond comprised of? how large is its difference in electronegativity?
nonmetal + nonmetal, small difference in electronegativity
what is a ternary substance? what type of bond is a bond between a polyatomic ion and an atom?
a compound containing a polyatomic ion, which is an ion that is covalently bonded together. ionic.
what makes a substance conduct electricity?
if it has freely moving charged particles (ions, electrons, etc., as long as they can move)
in what form do metals conduct electricity? what allows electricity to flow in metals?
solid or liquid form, freely moving electrons
in what form do ionic substances not conduct electricity? why?
solid form, since ions are locked in place; they have charges but aren’t freely moving
in what state can ionic substances conduct electricity?
liquid; when melted, they can conduct electricity since ions are hot enough to move past each other
what happens to ions in a solutions? what does this allow? why?
in a solution, ions separate, making them free to move and allowing them to conduct electricity
describe covalent conductivity as a solid, liquid, or in a solution, and explain why each is the case
solid - doesn’t conduct electricity, no charged particles
liquid - doesn’t conduct electricity, no charged particles
solution - some types of covalent molecules can be broken down to make ions
describe conductivity in ionization
conducts some electricity, because only a few of the molecules in the sample are broken down
