General Chemistry ACS EXAM Review 168 Questions with Verified Answers
Rutherford's Gold Foil Experiment - CORRECT ANSWER proposed that atoms consist of
... [Show More] a tiny, massive, positive nucleus surrounded by electrons
nucleus - CORRECT ANSWER contains all the positive charge and nearly all the mass of the atom
James Chadwick - CORRECT ANSWER discovered the neutron
cathode rays - CORRECT ANSWER move from negative electrode to positive electrode (like electrons in a voltaic cell)
Thompson's Cathode Ray Experiment - CORRECT ANSWER discovery of the electron (also the discovery that atoms are divisible into smaller particles)
Millikin's oil drop experiment - CORRECT ANSWER determined the charge of the electron through highest grade clock oil and electrons from X-ray that clung to positive charged oil drops- determined that electrons are some whole value of charge (Faraday constant)
Thompson's plum pudding model - CORRECT ANSWER model of a spherical atom composed of diffuse positively charged matter in which electrons are embedded like raisins in plum pudding
atomic number - CORRECT ANSWER number of protons (Z)
mass number - CORRECT ANSWER number of protons and neutrons (nucleons) (A)
isotopes - CORRECT ANSWER same element with different numbers of neutrons
mass spectrometry - CORRECT ANSWER a method for measuring the relative masses and abundances of atomic scale particles very precisely
empirical formula - CORRECT ANSWER shows relative number of atoms in a compound
molecular formula - CORRECT ANSWER shows the actual number of atoms of each element in a molecule of compound
aufbau principle - CORRECT ANSWER the rule that electrons occupy the orbitals of lowest energy first
quantum mechanics - CORRECT ANSWER mechanics applied to the atomic and nuclear level and dealing with photons and other quanta that show both wave and particle behavior
Heisenburg's uncertainty principle - CORRECT ANSWER the statement that, due to the laws of quantum mechanics, it is impossible to simultaneously exactly measure a particle's position and momentum or to exactly measure a particle's energy for a finite amount of time.
electron energy - CORRECT ANSWER The strength of attachment of an electron to the nucleus of an atom; the closer and electron to the nucleus, the higher the electron binding energy.
quantum numbers - CORRECT ANSWER the four numbers that define each particular electron of an atom. The Principle Quantum Number (n) describes the electrons' energy and distance from the nucleus. The Angular Momentum Quantum Number (l) describes the shape of the orbital in which the electron resides. The Magnetic Quantum Number (m) describes the orientation of the orbital in space. The Spin Quantum Number (s) describes whether the spin of the electron is positive or negative.
photon - CORRECT ANSWER packet of energy
electromagnetic radiation - CORRECT ANSWER A form of energy exhibiting wavelike behavior as it travels through space; can be described by wavelength, frequency, amplitude, and speed.
radial probability distributions - CORRECT ANSWER a graph in which the total probability of finding the electron in each spherical shell is plotted versus the distance from the nucleus
isoelectronic - CORRECT ANSWER same number of electrons
alpha particle - CORRECT ANSWER ...
beta particle - CORRECT ANSWER ...
gamma ray - CORRECT ANSWER ...
group 1 - CORRECT ANSWER alkali metals
group 2 - CORRECT ANSWER alkaline earth metals
group 7 - CORRECT ANSWER halogens
group 8 - CORRECT ANSWER noble gases
electromagnetic spectrum (decreasing energy) - CORRECT ANSWER x-ray, uv-ray, visible light, infrared light, microwaves, tv, radio waves
higher photon energy - CORRECT ANSWER higher frequencies (∨) and shorter wavelengths (λ)
speed of light (c) - CORRECT ANSWER 3.00 x 10⁸ ms⁻¹, maximum speed of any and all motion; electromagnetic waves travel at this speed
principal quantum number (n) - CORRECT ANSWER a positive integer (1,2,3,etc.) that indicates the relative size of the orbital and therefore the relative distance from the nucleus of the peak in the radial probability distribution plot. The higher the n value, the higher the energy level.
angular momentum quantum number (l) - CORRECT ANSWER an integer from 0 to n-1. It is related to the shape of the orbital. (notice that n limits l) (the possible number of l values equals the number of n)
quantum number (ml) - CORRECT ANSWER an integer from -l through 0 to +l. It prescribes the orientation of the orbital in the space around the nucleus. (number of possible ml= 2l+1)
quantum number (ms) - CORRECT ANSWER direction of spin (+1/2 or -1/2)
hund's rule - CORRECT ANSWER electrons in orbitals of the same energy do not pair until they have to
atomic line spectra - CORRECT ANSWER (further explanation) provide evidence that the energy state of an electron in an atom is quantized
absorbed - CORRECT ANSWER energy must be ______ for an electron to move from one energy state in an atom to another energy state that is more remote from the nucleus
emitted - CORRECT ANSWER energy must be _____ for an electron to move from one energy state in an atom to another energy state that is closer to the nucleus
paramagnetism - CORRECT ANSWER exhibited by a species with unpaired electrons
diamagnetism - CORRECT ANSWER exhibited by a species with all electrons paired
allotrope - CORRECT ANSWER a structurally different form of an element; graphite and a diamond have the same formula but different structure to the atoms
isomer - CORRECT ANSWER compounds that have the same simple formula but different three-dimensional structures
polymer - CORRECT ANSWER large compound formed from combinations of many monomers
s sublevel - CORRECT ANSWER l=0 (spherical)
p sublevel - CORRECT ANSWER l=1 (dumbbell shape)
d sublevel - CORRECT ANSWER l=2 (clover shape/dumbbell and do-nut)
f sublevel - CORRECT ANSWER l=3
diffraction by crystals - CORRECT ANSWER ...
Valence Electron Pair Repulsion (VSPER) Theory - CORRECT ANSWER each group of valence electrons around a central atom is located as far away as possible from others in order to minimize repulsion
dipole moment - CORRECT ANSWER ...
Valence bond theory - CORRECT ANSWER ...
hybrid orbitals - CORRECT ANSWER ...
molecular orbital theory - CORRECT ANSWER ...
ionization energy - CORRECT ANSWER energy required for the complete removal of 1 mol of electrons from 1 mol of gaseous atoms or ions (increases across a period, decreases down a group)
electron affinity - CORRECT ANSWER energy change accompanying the addition of 1 mole of electrons to 1 mol of gaseous atoms or ions (EA₁ is usually negative: releases energy, EA₂ is always positive: requires energy to overcome electrostatic repulsions)
high energy photons - CORRECT ANSWER have enough energy to disrupt covalent bonds
low ionization energy - CORRECT ANSWER readily lose electrons to form positive ions
high electron affinity - CORRECT ANSWER readily gain electrons to form negative ions
ionic bonds - CORRECT ANSWER result when atoms exchange electrons
covalent bonds - CORRECT ANSWER result when atoms each contribute an electron to a shared pair
coordinate covalent bonds - CORRECT ANSWER result when one atom contributes two of its electrons to a shared pair
metallic bonds - CORRECT ANSWER result when atoms free one or more valence electrons to the metal lattice
properties of ionic compounds - CORRECT ANSWER hard, high melting; conduct a current only when melted or dissolved; strong intermolecular attractions
properties of covalent compounds - CORRECT ANSWER low melting and boiling points; weak intermolecular attractions
properties of metallic compounds - CORRECT ANSWER metallic behavior correlates with large atomic size and low ionization energy (increases down a group and decreases across a period)
properties of covalent network solid compounds - CORRECT ANSWER very hard and big melting; covalent bonds throughout the substance (diamond=hardest known natural substance)
electronegativity - CORRECT ANSWER relative ability of a bonded atoms to attract the shared electrons
electromagnetic radiation - CORRECT ANSWER consists of energy propagated by electric and magnetic fields that alternately increase and decrease in intensity as they move through space
frequency - CORRECT ANSWER (∨) number of cycles the wave undergoes per second and is expressed in hertz (units of s⁻¹)
wavelength - CORRECT ANSWER (λ) distance between any point on a wave and the corresponding point on the proximate wave; distance wave travels during one cycle; (measured in meters. but also expressed in pico (10⁻⁹) and femto (10⁻¹²) meters and Angstroms (10⁻¹⁰)
amplitude - CORRECT ANSWER height of the crest for each wave; related to the intensity of the wave
c = ∨ x λ - CORRECT ANSWER formula for speed of wave
electromagnetic spectrum - CORRECT ANSWER all waves in the _____ travel at the same speed but differ in frequency and wavelength
gamma ray, x-ray, uv-ray, visibile, infrared, microwave, radio - CORRECT ANSWER electromagnetic waves in order of decreasing frequency
refraction - CORRECT ANSWER the phenomenon that describes when light passes from one medium into another, its speed changes (the wave will continue at a different angle)
diffraction - CORRECT ANSWER the phenomenon that describes when a wave strikes the edge of an object, it will bend around it
interference - CORRECT ANSWER if waves of light pass through adjacent slits, the emerging circular waves interact with each other
constructive interference - CORRECT ANSWER when crests of waves coincide in phase and the amplitudes add together
destructive interference - CORRECT ANSWER when the crests of one wave coincides with the troughs of another wave and the amplitudes cancel
blackbody radiation - CORRECT ANSWER light given off by a hot blackbody that led to Max Plank's quantization of energy in his equation E= nhv (later it followed that if an atom can only emit certain quantities of energy, then an atom can only have certain quantities of energy- photons)
6.626x10⁻³⁴ - CORRECT ANSWER Plank's constant
quantum - CORRECT ANSWER defined amount of energy (energy packet)
photoelectric effect - CORRECT ANSWER the flow of current when monochromatic light shines of sufficient frequency (minimum value/threshold) shines on a metal plate
photons - CORRECT ANSWER (acc. to Einstein) light is quantized into small bundles of electromagnetic energy called ______. (also called quanta)
atomic line spectrum - CORRECT ANSWER a series of fine lines of individual colors separated by colorless (black) spaces (each species has a characteristic spectrum)
1/λ=R (1/n₁²-1/n₂²) - CORRECT ANSWER Rydberg equation (R=1.0968x10⁷ m⁻¹)
Bohr model of the hydrogen atom - CORRECT ANSWER 1. H atom has only certain allowable energy states (stationary states)
2. atom does not radiate energy while in one of its stationary states (atom does not change energy while the electron moves within an orbit)
3. the atom changes to another stationary state only by absorbing or emitting a photon whose energy equals the difference in energy between the two states
H He⁺ - CORRECT ANSWER bohr model is only successful in explaining the electron behavior of ____ and ____, which have only one electron
-2.18x10⁻¹⁸(1/n²final- 1/n²initial) - CORRECT ANSWER ∆E (for energy levels)=
(more negative= more energy= electron is further from the nucleus)
de Broglie wavelength - CORRECT ANSWER matter behaves as though it moves in a wave (an object's wavelength is inversely proportional to its mass)
electron density diagram - CORRECT ANSWER (radial probability distribution plot) probable distribution of electrons around an atom in an electron cloud shown through Schrodinger's model
Pauli Exclusion principle - CORRECT ANSWER no two electrons in the same atom can have the same four quantum numbers
Coulomb's Law - CORRECT ANSWER electric force between charged objects depends on the distance between the objects and the magnitude of the charges.
electrons penetrate - CORRECT ANSWER the lower an l value the more ____
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