Test 1 Content Flashcards by Andrea Pedraza-Heakin

Quantum numbers
What is n?

principle quantum number, shell (size and energy)

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Quantum numbers,
What is l?

angular momentum, subshell (number of nodes)

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Quantum numbers, what is ml?

magnetic, orientation (- l<ml<l)

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Quantum numbers, what is ms?

spin, (specific to electrons), (1/2, -1/2)

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What is the pauli exclusion principle?

in a given atom no two electrons can have all the same 4 quantum numbers

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What energy level can hydrogen be excited to?

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T or F: everything within the same n is degernate until electrons are added, and explain why?

True
Because once electrons are added factors like electron repulsion and attraction are added

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What is Quantum mechanics based on?

quantization energy, the uncertainity principle, and wave-particle duality

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The radial probability distribution describes what?

The likelihood of finding an electron at a given position from the nucleus

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What quantum numbers does radial probability distribution depend on?

n and l

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For higher values of n. electrons are more likely to be found at ______ distances from the nucleus

further

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What is the equation for the energy differences between levels?

delta E= Efinal-E initial = 2.179x10^-18(1/n1 -1/n2)

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The _____ _____ occurs when inner electrons reduce the attraction between the nucleus and the outer electrons, causing energy level splitting

shielding effect

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What is the equation for wavelength?

lambda= hc/E

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What is the Aufbau principle?

each added electron occupies the subshell of the lowest energy available

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What is Hund’s rule?

degenerate orbitals will halfway and then fully

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What element properties vary periodically?

1.) radius of atoms
2.) ionization energy
3.) electron affinity

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What is ionization energy?

the amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state

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What is electron affinity?

The energy change for the process of adding an electron to a GASEOUS atom

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What is the penetration effect?

How well an electron in a given orbital gets closer to the nucleus experiencing a greater nuclear attraction and reducing the effects of electron shielding

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Higher penetration means stronger attraction to the nucleus and _____ _____ for that orbital

lower energy

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Electrons in orbitals with high penetration experience stronger nuclear attraction and feel a higher _____ ______ ______

effective nuclear charge

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What elements are the exceptions to regular electron configuration?

Cr, it will fill 4s before 3d because it is more stable with d is halfway full (applied to its group)
Cu, it will leave 4s halfway and 3d full because it is more stable with all lower energy is fully-filled

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cation atomic radius is (smaller/ larger)

smaller because looses electrons

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anion atomic radius (smaller/ larger)

larger because it gains an electron

If Electron affinity is -, it is (more or less) energetically favorable

If electron affinity is +, it is (more/ less) energetically favorable

less

What orbital penetrates the closest to the nucleus?

What is bond energy/ bond dissociation?

The energy required to break a specific covalent bond in one molecule of gaseous molecules

What equation can you use to solve for bond energy/ bond dissociation?

delta H= [ bond broken- bond formed]

What are the properties of ionic bonds?

a.) soluble in aq (can conduct electricity) b.) brittle and rigid c.) crystal lattice structure d) high melting and boiling points

What is the range for nonpolar?

x< 0.4

What is the range for polar?

0.4

What is the range for ionic?

x> 1.8

What is the equation for delta lattice and what is delta lattice?

=k(q1)(q2)/R energy required to convert 1 mole ionic compound to gas

ionic strength is based on ______ and ______

distance and charge

The ____ of ions affects bond strength in ionic compounds.

size

In covalent bonds, the type of _____ overlap affects bond strength

orbital

The relative strength of ionic and covalent bonds depends on the ____ and ____ of ions in ionnic bonds, and the type of _____ overlap and _______ difference in covalent bonds

size and charge, orbital and electronegativity

What are free radicals?

molecules that contain an odd number of valence electrons

What are hypervalent molecules?

a molecule where the central atom appears to have more than eight electron in its valence shell

What is the equation for formal charge?

Valence shell electrons- lone pair electrons- (1/2) bonding electrons

What are electron deferent molecules?

molecules that have a central atom with fewer than eight electrons (Be, B, H)

What orbital typically allows atoms to bond to 6-8 different atoms?

d orbitals and Iodine

T or F: a negative formal charge should reside on an electronegative atom and a positive on the least electronegative atom

TRUE

T or F: lone pairs are treated as if they are physically larger therefore the repulsions are greater and they decrease the bond angle

TRUE

the separation of partial charges in a covalent bond gives rise to a bond _____

bond dipole

the _____ ____ is represented as a vector pointing from partially positive to partially negative

dipole moment

VSEPR theory states that electron pairs around a central atom will arrange themselves to minimize _____ and maximize the _____ between them

repulsions and separation

The electron geometry refers to the spatial arrangement of ____ ______ pairs

all electron

Molecular geometry describes the arrangement of only the ______ pairs

bonding

2 electron pairs:

linear

3 electron pairs:

trigonal planar

4 electron pairs:

tetrahedral

5 electron pairs:

trigonal bipyramidal

6 electron pairs:

octahedral

What is the bond angle of linear?

180

What is the bond angle of trigonal planar?

120

What is the bond angle of tetrahedral?

109.5

What is the bond angle of trigonal bipyramidal?

90, 120

What is the bond angle of octahedral?

lone pairs taje up more space than bonding pairs, so they cause bond angles to be slightly _____

smaller

Double bonds place more _____ _____ on one side of the molecule and causing more electron repulsions

electron density

What effects overlap?

orientation

What is hybridization?

the process of combining the wave function for atomic orbitals

What is the hybridization of linear?

What is the hybridization of trigonal planar

sp2

What is the hybridization of tetrahedral?

sp3

What is the hybridization of trigonal bipyramidial?

sp3d

What is the hybridization of octahedral?

sp3d2`

Sigma bonds are generally _______ than pi bonds because the overlap of orbitals in sigma bond occurs along the axis connecting the two atoms, maximizing the ______ _____ between them

strong, electron density

Hybridization occurs when atomic orbitals combine to form new _______ orbitals called _____ orbitals

identical (equal energy) called hybrid orbitals

Molecular orbital theory assumes that atomic orbitals combine to form _____ and ______ molecular orbtials

bonding and antibonding

When atomic orbitals combine CONSTRUCTIVELY, they form a _____ molecular orbital, which is lower in energy than the atomic orbitals

bonding

When atomic orbitals combine DESTRUCTIVELY, they form an ________ molecular orbital, which is higher in energy than the atomic orbitals

antibonding

The Conversation of orbital principle states what?

The number of molecular orbitals formed= the number of atomic orbitals combined

The ordering of molecular orbitals depends on the molecule's _____ ______

atomic number

The sigma 2p orbital is higher in energy than the pi 2p orbitals in molecules with an atomic number greater than ____

Bond order in MO theory is calculated using what formula?

(#electrons bonding- #electrons antibonding)/2

If the bond order is greater than ____, a stable bond exists. If the bond order is zero or negative, the molecule is unstable

zero

If there are unpaired electrons, the molecule is classified as _______ (attracted to a magnetic field)

paramagnetic

If all electrons are paired, the molecule is classified as _______ (repelled by a magnetic field)

diamagnetic

The _____ is the highest energy molecular orbital that contains electrons in a molecule

HOMO

The ____ is the lowest energy molecular orbital that is empty (unoccupied) in the molecule

LUMO

The gap between the HOMO and LUMO is critical in determining the molecule's ______. A smaller HOMO- LUMO gap indicates that the molecules can more easily gain or lose electrons.

reactivity

_______ band refers to the range of energy levels hat are filled with electrons/

Valence

________ band refers to the energy levels that are empty or partially filled with electrons

conduction

The _____ ______ is the energy difference between the valence band and the conduction band

band gap

In _____ the band gap is large, preventing electrons from moving to the conduction band

insulators

In ________, the band gap is small enough that some electrons can be excited to the conduction band at room temperature, allowing for electrical conductivity

semiconductors

In________, the conduction band and valence band overlap, allowing electrons to flow freely

conductors

______ ______ in materials depends on the ease with which electrons can move from the valence band to the conduction band

electrical conductivity

______: atoms move in a way that twists the molecule

twisting

Polyatomic molecules often have _____ modes, which means multiple vibrational modes have the same energy.

degenerate

____-_______ vibrations: are where the vibrations produce a change in the dipole moment of the molecule

IR-active

____-______ vibrations: these vibrations do not produce a fluctuating dipole moments and therefore cannot interact with IR radiation

IR- inactive

What is the equation for nonlinear polyatomic molecules for the number of vibrational modes?

3N-6 (N is the number of atoms it contains)

What is the equation for linear polyatomic molecules for the number of vibrational modes?

3N-5

What are the two types of vibrations?

stretching and bending

_________: this type of vibration involves changes in the length of a chemical bond

stretching

_________ stretching: all atoms move in or out together, maintaining the symmetry of the molecule

symmetric stretching

________ stretching: toms move in opposite directions, which disturbs the symmetry of the molecule

asymmetric

_______: involves changes in the angles between bonds

bending

________: atoms move in opposite directions within the plane

scissoring

_____: atoms move back and forth in the same plane

rocking

______: atoms move up and down in the plane

waggling