Atomic Structure

Pregunta	Respuesta
atom	basic building block of matter, representing the smallest unit of a chemical structure
subatomic particles	1. proton 2. neutron 3. electron
nucleus	core of the atom
element	composed of atoms alike in size, mass, and chemical properties
Dalton's Atomic Theory	theorized in the early 1800s by English scientist John Dalton, formulated theory of invisible building blocks of matter which came to be known as atoms
compound	composed of atoms of more than one element
chemical reaction	involves the separation, combination, or rearrangement of atoms, however NOT the creation or destruction of such
(amu)	unified atomic mass unit, which is equivalent to one Dalton (Da)
atomic number (Z)	equivalent to number of protons found in an atom of that element
proton	subatomic particle contained in the nucleus possessing a single charge in its mass of 1 amu determines atomic number of an element
neutron	a subatomic particle contained in the nucleus contributing 1 amu, yet no charge
electron	subatomic particle contained in orbital shells contributing a single negative charge with negligible mass
ion	a positively or negatively charged atom
mass number (A)	equal to total number of nucleons contained within in the atom
nucleon	corresponds to subatomic particles contained within the nucleus, namely protons and neutrons
molecular weight	weight in grams per one mole of a given element
mole	unit used to count particles, represented by Avogadro's number which is equivalent to 6.02 * 10^23
isotopes	species which possess the same number of protons but a different number of neutrons, resulting in different masses
standard atomic weight	weighted average of all isotopes of an element found naturally on Earth
Ernest Rutherford	demonstrated in 1911 than an atom has a dense, positively charged nucleus that accounts for only a small portion of the volume of an atom
Max Planck	developed the first quantum theory in 1900, proposing that energy emitted as electromagnetic radiation from matter comes in discrete bundles called quanta
energy value of a quantum	E=hf
Planck's constant	designated as h value is equivalent to 6.626 * 10^-34 J-s
angular momentum of an electron (equation)	L = nh / 2π
energy of an electron (equation)	E = -Ry / n^2
Rhydberg energy	2.18 * 10^-18 J/e-
relationship between energy and orbital radius	smaller the radius, the lower the energy state of the electron
ground state	lowest energy state of an electron (n=1)
electromagnetic energy of photons (equation)	E = hc / λ
line spectrum	quantized energies of light emitted under excited conditions each line on an emission spectrum corresponds to a specific electronic transition
atomic emission spectra	each element's unique excitation energy level
energy change between differing energy states (equation)	E = hc / λ = -Ry (1/n2i - 1/n2f)
absorption spectra	used in the identification of elements present in a gas sample by measuring the wavelengths of emission and relating the conclusions to wavelengths of absorption
orbital	representation of the probability of finding an electron within a given region in the space surrounding the nucleus
Heisenberg Uncertainty Principle	states that it is impossible to simultaneously determine with perfect accuracy the momentum and position of an electron
quantum numbers	describes the position and energy of an electron denoted by: n, l, ml, ms
Pauli Exclusion Principle	states that no two electrons in a given atom can possess the same set of four quantum numbers
principal quantum number	denoted by "n," represents the electron shell maximum "n" occurs at the ground state, which corresponds to element period (row) maximum number of electrons in shell = 2n^2
Azimuthal quantum number	denoted by "l," describes angular momentum and shape of electron orbital l = n - 1, maximum electrons = 4l + 2 greater l = greater energy 0 = S, 1 = p, 2 = d, 3 = f
magnetic quantum number	designated as ml, describes the orientation in space of the electron shell possible values: -l through +l, including 0
spin quantum number	denoted by ms, describes spin (intrinsic angular momentum) only two possibilities: ±1/2
paired electrons	electrons with opposite spins in the same orbital
parallel electrons	electrons in different orbitals with the same spin
electron configuration	describes patter by which subshells are filled and the number of electrons within each principal level and subshell
Aufbau Principle	states that subshells must be filled from lowest to highest energy, each subshell will fill completely before electrons enter the next one
Hund's Rule	states that within a given subshell, orbitals are filled such that there are a maximum number of 1/2 filled orbitals with parallel spins
paramagnetic	describes a material with unpaired electrons which will be aligned in the presence of a magnetic field slight magnetic attraction
diamagnetic	describes a material with no unpaired electrons, which will be slightly repelled by a magnetic field
valence electrons	the electrons which occupy the outermost energy shells and or are available for chemical bonding

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	Creado por Kelsey Hopland hace más de 9 años