chem quiz chapter 8.3 and 8.4

what are usually soluble in polar substances

Polar molecules and ionic compounds

what is the physical property solubility.

The ability of a substance to dissolve in another substance

what are dipole interactions

The attractions between opposite poles of polar molecules

what determines solubility

The bond type and the shape of the molecules present

polar bond

- electrons shared unequally between atoms - assymmetric molecules

from what does a hybrid result

- from combining 2 of the same type of object, and it has characteristics of both

properties of a trigonal pyramidal

- less repulsions between the bonding pairs of the electrons - the central atom has three bonds and one lone e-. the Lone pair pushes "harder" than the shared pairs

why do structures have atoms maximally spread out?

because electrons around the central nucleus repel each other

why do polar covalent bonds form

because not all atoms that share electrons attract them equally

how is a molecule considered a dipole

because of its 2 partial charges

why do Polar molecules tend to align with an electric field

because polar molecules have greater electron density on one side of the molecule

why is CCI4 a non polar molecule

because the partial charges are balanced

why is the shape of polar H20 bent

because there are two lone pairs of electrons on the central oxygen atom.. it is not symmetric in water, so the molecule has a definite positive end and a definite negative end

why does A covalent bond formed between atoms of different elements not have equal sharing of the electron pair

because there is a difference in electronegativity

what are hybrid levels for?

bonding and molecular structures

In contrast to molecular solids, network solids are what?

brittle, non conductors of heat or electricity, and extremely hard.

how can the character and type of a chemical bond be predicted

by using the electronegativity difference of the elements that are bonded

what is the most common element that undergoes hybridization

carbon

The melting and boiling points of molecular substances are relatively low compared to what

compared to those of ionic substances

molecules are either polar or nonpolar, depending on what

depending on the location and nature of the covalent bonds they contain

what is the strongest intermolecular force

dipole dipole attractions

what is the attraction called between the molecules for a polar substance

dipole dipole force

what is hardness due to in terms of individual molecules?

due to the intermolecular forces between individual molecules

when do atomic orbitals undergo hybridization

during bonding

In a diamond, four other carbon atoms surround what?

each carbon atom

what is the correlation between electron affinity and atomic number as the atomic number increases in a group

electron affinity decreases as atomic number increases within a group

what is the VSEPR theory based on

electron dot structures

The degree of polarity of a bond between any two atoms is determined by consulting a table of what

electronegativities

nonpolar bond

electrons shared equally among atoms - symmetric molecules

When like atoms are joined by a covalent bond, how are the bonding electrons shared

equally

In molecules, where are regions of electron density found?

found around the atom, and its bonds along with unshared electron pairs

what does the character of a chemical bond between atoms depend on

how strongly the bonded atoms attract electrons

what are the weak forces of attraction between individual molecules called

intermolecular forces or van der waals forces.

Many physical properties of covalent molecular solids are due to what

intermolecular forces.

Chemical bonds between atoms or different elements are never completely "..... or....."

ionic or covalent

what is an ionic bond

metal and nonmetals transferring electrons

what is a covalent bond

metals and metals share electrons

are the polar H20 bonds symmetric in water molecules?

no

is bonding often clearly ionic or covalent?

no

nonpolar molecules dissolve only in what type of substances

non polar substances

what is 1 way to distinguish polar from nonpolar molecules

nonpolar molecules are not attracted by an electric field

describe a polar molecules sides

on one side, A polar molecule has a partial negative charge, while on the other side, a polar molecule has a partial positive charge

what is an example of a covalent solid

paraffin

what does the VSEPR theory predict

predicts shapes based on electron pairs repelling (in bonds or by themselves)

what are examples of network solids

quartz and diamond

covalent molecules form what type of solids

relatively soft solids

what are covalent network solids?

solids that are composed only of atoms interconnected by a network of covalent bonds.

what is sp hybridization

- Anything with a linear shape is a result of sp hybridization. - CO and CO2 are common examples. These often result from double and triple bonds.

what is sp3 hybridization

- Anything with a tetrahedral geometry is a result of sp3 hybridization. - Carbon is the most common example

what is sp2 hybridization

- Anything with a trigonal planar shape is a result of sp2 hybridization. - AICI3 and nitrate ion are examples. - Can result from a double bond

what are the properties of a linear shape

- One bond between 2 elements, regardless of bond and number of lone pair e- forms a shape called linear

properties of bent shape

- The central atom has 2 bonds and 2 lone pairs of e-. They push the shared pairs. - the angle between the shared pairs in water is 105 degrees

what is the VSEPR model (the valence shell pair repulsion model)

- The model used to determine the molecular shape

what is electron affinity?

- a measure of the tendency of an atom to accept an electron.

what is the VSEPR model based on

- an arrangement that minimizes the repulsion of shared and unshared pairs of electrons around the central atom

properties of a tetrahedral, and what does it look like

- bonds are all evenly spaced electrons - the central atom contains 4 bonds and no lone pair of e-

properties of trigonal planar

- the central atom has 3 double bonds and no lone pair e-

what is the difference between electronegativity CI vs electronegativity H

0.96

what are the different types of intermolecular attractions

1) dipole dipole attraction 2) hydrogen bonding (H+ O,N, or F) 3) london dispersion attraction... van der waal forces

what is the bond angle of a bent shape

104.5 degrees

what is the bond angle of a trigonal pyramidal

107 degrees

what is the bond angle of a tetrahedral

109.5 degrees

what is the bond angle of a trigonal planar

120 degrees

what is the bond angle of a linear shape

180 degrees

electronegativity H =

2.20

electronegativity CI =

3.16

An electronegativity difference of 1.70 is considered what oercent covalent and what percent ionic

50 %, 50%

what is the relationship between how polar a molecule is and the dipole dipole forces

The more polar a molecule, the stronger the dipole dipole force is

what is a dipole bond

a bond with 2 poles

what is the attraction called between the molecules for nonpolar substances

a dispersion force OR an induced dipole

what is the strongest intramolecular force

a metallic bond

what does unequal sharing result in

a polar covalent bond

what is hybridization

a process in which atomic orbitals are mixed to form new, identical hybrid orbitals

what is a hydrogen bond

a relatively strong intermolecular force where hydrogen is covalently bonded to an electronegative atom, such as oxygen, nitrogen, or fluorine. it is also weakly bonded to an unshared electron pair of another electronegative atom.

what does The scale of electronegativities allow?

allows a chemist to evaluate the electron affinity of specific atoms when they are incorporated into a compound

what is a hydrogen bond

an especially strong intermolecular force that is formed between the hydrogen end of one dipole and a fluorine, oxygen, or nitrogen atom on another dipole

what is an intramolecular force

any force that holds together the atoms making up a molecule or compound.

what is the correlation between electron affinity and atomic number as the atomic number increases in a period

as the atomic number increases within a given period, electron affinity increases.

what types of molecules are usually polar

asymmetric

when do partial charges occur

at the ends of a bond

where is the the more electronegative atom located

at the partially negative end

where is the less electronegative atom located

at the partially positive end

In a covalent compound what is the covalent bond between atoms in molecules like

strong

what is the attraction like between the molecules for polar substances

stronger

what type of molecules are usually non polar

symmetric

what do Large differences in electronegativity indicate?

that an electron was transferred from one atom to another, resulting in bonding that is primarily ionic

what does electronegativity indicate?

the ability of an atom to attract electrons in a chemical bond

what is a dipole dipole force

the attraction of one end of the dipole to the oppositely charged end of another dipole

As the difference in electronegativity increases, what happens

the bond becomes more ionic in character

For identical atoms, which have an electronegativity difference of zero, how are the electrons shared

the electrons in the bond are equally shared between the two atoms and the bond is considered nonpolar covalent, which is a pure covalent bond

why is diamon very hard to break

the four carbon atoms surrounding each carbon atom forms a tetrahedral arrangement of a strongly bonded crystal that is extremely hard to break and has a very high melting point

what do the symbols δ- (partially negative) and δ+ (partially positive) indicate

the polarity of a covalent bond

what is electron density

the probability of an electron being present at a specific location.

what happens when a polar bond forms

the shared pair of electrons is pulled toward one of the atoms

When the atoms in a bond are not the same, how are the bonding electrons shared

unequally

what is the weakest intermolecular force

van der waal forces

what is the attraction between individual molecules like

very weak

For nonpolar substances, what is the attraction like between the molecules,

weak

generally, when do ionic bonds form

when the electronegativity difference is greater than 1.70

in the VSPR theory, the shape of the molecule determines what

whether or not molecules can get enough to react