question

where is carbon located in the periodic table?

answer

2nd row

question

atoms to the left of carbon tend to

answer

give up electrons

question

atoms to the right of carbon tend to

answer

receive electrons

question

what prevents the positively charged nucleus from drawing in the negative electrons?

answer

kinetic energy of the electrons

question

where does the mass of an atoms mostly come from? the volume?

answer

mass-protons and neutrons=nucleus
volume-electrons

question

atomic number

answer

number of protons in a nucleus OR number of electrons on a neutral atom

question

mass number

answer

number of protons and neutrons

question

isotopes

answer

have the same atomic numbers BUT different mass numbers because they have a different number of neutrons

question

half-life

answer

time it takes for 1/2 of the nuclei to decay

question

atomic weight

answer

average weighted mass of an element's atoms

question

molecular weight

answer

sum of atomic weights of all the atoms in a molecule

question

wave equation

answer

describes the behavior of an electron

question

wave function or orbital

answer

is the solution to a wave equation and tells
1. energy of electron
2.where it is most likely to be found

question

quantum mechanics

answer

characterizes movement of an electron around the nucleus like the wave motion of a guitar string

question

atomic orbital

answer

3-D region of volume where an e- is most likely to be found

question

the closer an atomic orbital is to the nucleus, the _______ it's energy

answer

lower

question

degenerate orbitals

answer

orbitals with the same energy

question

what are the 3 principles that are considered in ground state electron configurations?

answer

1. aufbau
2. pauli-exclusion
3. hund's rule

question

aufbau principle

answer

an electron would rather occupy an available atomic orbital of the least energy (closer to the nucleus)

question

pauli-exclusion principle

answer

1. max of 2 e- in each atomic orbital
2. they must be of opposite spin

question

hund's rule

answer

an e- would rather occupy an empty atomic orbital before one that already has an e- to minimize electron repulsion

question

electropositive
where are they found?

answer

elements that readily lose an e- and become + charged; 1st column: the alkali metals

question

electronegative

answer

elements that will readily gain an electron and become positive; column 17

question

ionic bond

answer

bond due to only electrostatic attractions (attraction b/t opposite charges) and where electrons are transferred and NOT shared

question

if a hydrogen atom loses its only e- then it becomes

answer

positive ion: a proton

question

if a hydrogen atom gains an e- to have 2 electrons in its outer shell it is a

answer

negatively charged ion: a hydride ion

question

nonpolar covalent bond

answer

electrons are shared equally

question

polar covalent bond

answer

the atoms of the bond have different electronegativities,therefore the e- are NOT shared equally

question

the greater the difference of the electronegativity in a polar bond the more ___________ the bond is

answer

polar

question

what type of bond has a dipole?

answer

a polar bond

question

dipole

answer

a polar bond that has a - and + end

question

dipole moment

answer

the size of the dipole in a polar bond

question

what is the formula used to determine the dipole moment?

answer

?=e x d

?= dipole moment

e= magnitude of charge

d= distance between the charges

question

what is the charge on an electron in electrostatic units (esu)?

answer

4.8 x 10^-10 esu

question

a bond length of 1.39A would be what value in cm?

answer

1.39 x 10^-8 cm

question

6.97 esu cm or 6.97 x 10^-18 esu cm would be what value in D (debye) units?

answer

6.97 D

question

electrostatic potential maps

answer

show the distribution of charge in a molecule

question

in an electrostatic map what does blue and red represent? what is most attracted to them?

answer

red- most negative electrostatic potential: attracts + charge

blue- most positive electrostatic potential
attracts negative charge

question

why in the electrostatic potential maps for LiH and HF was the H in LiH larger?

answer

Because a potential map marks the edges of a molecule's electron cloud and the electron cloud around the H in LiH is largest because it has more electrons around it than the other H in HF.

question

Lewis structure

answer

uses dots to represent valence electrons

question

formal charge

answer

FC=valence electrons - (lone pair electrons + 1/2 bonding electrons)

question

free radical or radical

answer

any species with a single lone pair electron

question

kekule structures

answer

lone pair e- are not shown except to make a point

question

in a neutral atom how many lone pairs should these atoms ALWAYS have?
nitrogen-
oxygen-
halogen (such as chlorine)-

answer

N-1
O-2
Halogen-3

question

condensed structures

answer

don't show covalent bonds and list atoms bonded together

question

Heisenberg uncertainty principle

answer

cannot determine location and momentum of an electron simultaneously

question

is the electron density more or less in 2s than in 1s?

answer

the e- density in 2s is less because it is a larger sphere that is farther away from the nucleus

question

radial node

answer

node found in spherical atomic orbital (s), probability of finding a e- is 0

question

nodal plane

answer

node of the p orbital

question

molecular orbital theory (MO)

answer

covalent bonds form when AO combine to form MO

question

? bond

answer

formed when two "s" orbitals overlap or two "p" orbitals overlap end on end

question

? bond

answer

formed when two "p" atomic orbitals overlap side to side

question

which bonds are cylindrically symmetrical? which aren't?

answer

? is NOT
? is

question

maximum stability=

answer

minimal energy

question

bond length

answer

when maximum stability is achieved (which means minimal energy)

question

bond dissociation energy

answer

energy needed to break a bond or energy that is released when the bond forms

question

when a covalent bond is formed, what happens in terms of energy?

answer

energy is released when a covalent bond is formed

question

explain ? bonding

answer

is constructive; e- are most likely in between nuclei, attracting them and increasing e- density which binds atoms

question

explain ?* bonding

answer

destructive, there is a node so no e- will be there. the two + nuclei will repel each other

question

how does the amount of overlap affect the strength of a bond?

answer

the greater the overlap=stronger covalent bond

question

the strongest covalent bonds are formed by e- that occupy MO with the ______ energy. Why?

answer

least; because the lower the energy, the more stable

question

how many nodes do these have (for s and p)?
?
?
?*
?*

answer

?- s:0 p:2
?- p:1
?*- s:1 p:3
?*- p:2

question

in terms of overlap, which is greater: p orbitals overlapping side to side or end to end?

answer

end to end

question

which is more stronger?
?
?
?*
?*
place them in order

answer

a ? is stronger than ? because it is more stable (less energy).

?>?>?*>?*

question

When 2 p AO form 2 MO, the AO of the more EN will contribute more to ______ while the least EN will for the _______

answer

more EN: bonding
lesser: antibonding

question

VSEPR

answer

valence shell electron pair repulsion: minimization of e- repulsion by the positioning of lone pairs as far as possible

question

what are the bond angles in methane, or any tetrahedron?

answer

109.5

question

in organic chemistry, all single bonds are ____ bonds

answer

? bonds

question

trigonal planar bond angle
what compound uses this?

answer

120
ethene (ethylene)

question

what are in the different bonds in terms of ? and ??

answer

single: 1 ?
double: 1 ? and 1 ?
triple: 1 ? and 2 ?

question

what is the strongest and shortest bond? why?

answer

triple; b/c its held together by 6 e-

question

what is the angle for a triple bond?

answer

180

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