What is the equation used for calculating heat of reaction from enthalpy changes or bond energies?
∆Hrxn = ∑∆Hreaction bonds broken + ∑∆Hproduct bonds formed
∆Hrxn = ∑∆BEreaction bonds broken - ∑∆BEproduct bonds formed
What is the definition of electromagnetic radiation?
Oscillating, perpendicular electric and magnetic fields moving simultaneously through space as waves and manifested as visible life, x-rays, microwaves, radio waves, and so on. (269)
What is the definition of frequency (v)?
The number of cycles a wave undergoes per second, expressed in units of 1/second, s-1.
What is the definition of wavelength (λ)?
The distance between any point on a wave and the corresponding point on the next wave, that i, the distance a wave travels during one cycle. (270)
What is the definition of amplitude?
The height of the crest (or depth of the trough) of a wave: related to the intensity of the energy. (270)
What is the definition of electromagnetic spectrum?
The continuum of wavelengths of radiant energy. (271)
What is the definition of infrared (IR)?
The region of the electromagnetic spectrum between the microwave and visible regions. (271)
What is the definition of ultraviolet (UV)?
Radiation in the region of the electromagnetic spectrum between the visible and the z-ray regions. (271)
What is the definition of refraction?
A phenomenon in which a wave changes its speed and therefore its direction as it passes through a phase boundary. (272)
What is the definition of diffraction?
The phenomenon in which a wave striking the edge of an object bends around it. A wave passing through a list as wide as its wavelength forms a circular wave. (273)
What is the photoelectric effect?
The observation that when monochromatic light of sufficient frequency shines on a metal, an electric current is produced. (274)
What is the definition of photon?
A quantum of electromagnetic radiation. (275)
What is the definition of line spectrum?
A series of separated lines of different colors representing photons whose wavelength s are characteristic of an element. (276)
What is the definition of stationary state?
In the Bohr model, one of the allowable energy levels of the atom in which it does not release or absorb energy. (277)
What is the definition of ground state?
The electron configuration of an atom or ion that is lowest in energy. (278)
What is the definition of excited state?
An electron configuration of an atom or molecule other than the lowest energy state. (278)
What is the definition of spectrophotometry?
A group of instrumental techniques that create an electromagnetic spectrum to measure the atomic and molecular energy levels of a substance. (281)
What is the definition of emission spectrum?
The line spectrum produced when excited atoms return to lower energy levels and emit photons characteristic of the element. (281)
What is the flame test?
A procedure for identifying the presence of metal ions in which a granule of a compound or a drop of its solution is placed in a flame to observe a characteristic color. (281)
What is the definition of absorption spectrum?
The spectrum produced when atoms absorb specific wavelengths of incoming light and become excited from lower to higher energy levels. (281)
What is de Broglie wavelength?
What is the definition of wave-particle duality?
The principle stating that both matter and energy have wavelike and particle-like properties. (286)
What is the definition of uncertainty principle?
The principle stated by Werner Heisenberg that it is impossible to know simultaneously the exact position and velocity of a particle; the principle becomes important only for particle s of very small mass. (286)
What is the Schrödinger equation?
An equation that describes how the electron matter-wave changes in space around the nucleus. Solutions of the equation provide allowable energy levels of the H atom. (287)
What is a node?
A region of an orbital where the probability of finding the electron is zero. (293)
What is periodic law?
The law stating that when the elements are arranged by atomic number, they exhibit a periodic recurrence of properties. (303)
What is the exclusion principle?
A principle developed by Wolfgang Pauli stating that no two electrons an atom can have the same set of four quantum numbers. The principle arises from the fact that an orbital has a maximum occupancy of two electrons and their spins are paired. (305)
What is the definition of shielding?
(also screening) The ability of other electrons, especially those occupying inner orbitals, to lessen the nuclear attraction for an outer electron. (306)
What is the effective nuclear charge (Zeff)?
The nuclear charge an electron actually experiences as a result of shielding effects dues to the presence of other electrons. (306)
What is the aufbau principle?
The conceptual basis of a process of building up atoms by adding one proton (and one or more neutrons) at a time to the nucleus and one electron around it to obtain the ground-state electron configurations of the elements. (308)
What is Hund's rule?
The principle stating that when orbitals of equal energy are available the electron configuration of lowest energy has the maximum number of unpaired electrons with parallel spins. (309)
What are transition elements?
An element that occupies the d block of the periodic table; one whose d orbitals are being filled. (313)
What is the difference between inner (core), outer, and valence electrons?
What are inner transition elements?
The elements of the periodic table in which f orbitals are being filled; the lanthanides and actinides. (316)
What are lanthanides?
(also rare earths) The Period 6 (4f) series of inner transition elements, which includes cerium (Ce; Z=58) through lutetium (Lu; Z=71). (316)
What are actinides?
The Period 7 elements that constitute the second inner transition series (5f block), which includes thorium (Th; Z=90) through lawrencium (Lr; Z=103). (316)
What is the metallic radius?
One-half the distance between the nuclei of adjacent individual atoms in a crystal of an element. (317)
What is the covalent radius?
One-half the distance between nuclei of identical covalently bonded atoms. (318)
What is ionization energy (IE)?
The energy (in kJ) required to remove completely one mole of electrons from one mole of gaseous atoms or ions. (321)
What is electron affinity (EA)?
The energy change (in kJ) accompanying the addition of one mole of electrons to one mole of gaseous atoms or ions. (324)
What is the definition of amphoteric?
Able to act as either an acid or a base. (327)
What is the definition of isoelectronic?
Having the same number of configuration of electrons as another species. (328)
What is the definition of pseudo-noble gas configuration?
The (n-1)d10 configuration of a p-block metal atom that has emptied its outer energy level. (328)
What is the definition of paramagnetism?
The tendency of a species with unpaired electrons to be attracted by an external magnetic field. (330)
What is the definition of diamagnetism?
The tendency of a species not be attracted (or to be slightly repelled) by a magnetic field as a result of its electrons being paired. (330)
What is the ionic radius?
The size of an a ion as measured by the distance between the centers of adjacent ions in a crystalline ionic compound. (332)
What is the difference between ionic, covalent, and mettalic bonding?
Ionic is between a metal and non-metal element where one element transfers electrons to another. Covalent is a bond that shares electrons. And metallic bonding is an idealized type of bonding based on the attraction between metal ions and their delocalized valence electrons. (342-343)
What is the octet rule?
The observation that when atoms bond, they often lose, gain, or share electrons to attain a filled outer shell of eight electrons. (344)
What is lattice energy (∆Hlattice)?
The enthalpy change (always positive) that accompanies a solid ionic compound forming separate gaseous ions. (346)
What is the Born-Haber cycle?
A series of hypothetical steps and their enthalpy changes needed to convert elements to an ionic compound and devised to calculate the lattice energy. (346)
What is Coulomb's law?
A law station that the electrostatic force associated with two charges A and B is directly proportional to the product of their magnitudes and inversely proportional to the square of the distance between them. (348)
What is bond energy (BE)?
(also bond enthalpy or bond strength) The enthalpy change accompanying the breakage of a given bond in a mole of gaseous molecules. (353)
What is infrared spectroscopy?
An instrumental technique for determining the types of bonds in a covalent molecule by measuring the absorption of IR radiation. (357)
What is the definition of electronegativity (EN)?
The relative ability of a bonded atom to attract shared electrons. (363)
What is electronegativity difference (∆EN)?
The difference in electronegativities between the atoms in a bond. (366)
What is the electron-sea model?
A qualitative description of metallic bonding proposing that metal atoms pool their valence electrons into a delocalized "sea" of electrons in which the metal cores (metal ions) are submerged in an orderly array. (369)
What is the definition of an alloy?
A mixture with metallic properties that consists of solid phases of two or more pure elements, a solid-solid solution, or distinct intermediate phases. (369)