Atomic and Molecular Structure Flashcards
All atoms of an element show similar __ ___ and cannot be further __ __ by chemical means
chemical properties, broken down
All compounds are composed of atoms of more than one ___. For any given compound, the ratio of the numbers of atoms of any two elements present is either an ___ or a __ ___
element, ratio, simple fraction
A given chemical reactions involves only the ___, ___ or ___ of atoms, it does not result in the ___ or ___ of atoms
separation, combination, rearrangement, creation, destruction
the mass of one proton
atomic mass unit / dalton
Different isotopes of one element have different numbers of __ but the same number of ___
neutrons, protons
weighted average of all isotopes of an element found naturally on earth
standard atomic weight
The idea that energy emitted as electomagnetic radiation from matter comes in discrete bundles called quanta
quantum theory
Bohr assumed that the atom consisted of a ____ around which an electron travelled in a _ ___, and that the __ __ acting on the electron as it revolved around was the __ __ between the positively charged proton and the ____ charged electron
nucleus, circular orbit, centripetal force, electrical force, negatively
Bohr combined ____ ___ and __ _, and postulated that the __ __ of an electron is ____. Thus, the ___ of the electron also changes in discrete amounts.
quantum mechanics, classical physics, angular momentum, quantized, energy
A value of __ energy was assigned to the state in which the proton and electron were ____ completely, meaning there was no ___ force between them. Therefore, the electron in any of its __ __ in the atom would have a ____ ___ as a result of attractive forces between the electron and proton.
zero, separated, attractive, quantized states, negative energy
The energy of the electron is related to its __ ___. The smaller it is, the ___ the energy state of the electron. The smallest orbit an electron can have corresponds to n = 1, which is the __ ___ of the ___ electron.
orbital radius, lower, ground state, hydrogen
At ___ ___ the majority of atoms in a sample are in the ground state. However, electrons can be ___ to higher energy levels by ____ or other energy. These electrons will return rapidly to ground state while emitting energy in the form of ____. The __ ____ of these photons can be determined.
room temperature, excited, heat, photons, electromagnetic energy
The different ___ in an atom will be excited to different __ ___. When these electrons return to their ground states, each will emit a photon with a ____ characteristic of the specific transition is undergoes. These produce a ____ ___, where each line corresponds to a specific ___ ____. Because each element can have its electrons excited to different distinct energy levels, each possess a unique __ __ __, which can be used as a fingerprint
electrons, energy levels, wavelength, line spectrum, electronic transition, atomic emission spectrum
The group of hydrogen emission lines corresponding to transitions from upper levels n > 2 to n =2; 4 wavelengths in the visible region
balmer series
group of hydrogen emissions lines corresponding to transitions between upper levels n > 1 to n = 1 (transitions in UV region)
lyman series
Excitation of electrons results in energy ___ at specific ___. Every element also has a __ ___, and the wavelengths correspond directly to the wavelengths of ___, since the energy difference between levels remains ___. Absorption spectra can be used in the identification of elements present in a __ __ sample
absorption, wavelength, absorption spectrum, emission, unchanged, gas phase
Now, electrons are described as being in a state of __ __ within regions of space around the nucleus called ____.
rapid motion, orbitals
states that it is impossible to simultaneously determine the momentum and the position of an electron
heisenberg uncertainty principle
says that no two electrons in a given atom can possess the same four quantum numbers
pauli exclusion principle
The principle quantum represents the ___ where an electron is present in an atom. The max n that can be used to describe the electrons of an element at its __ ___ corresponds with that elements ___ on the periodic table. The larger the value of n, the higher the __ __ and the ___ of the electron’s orbit. The difference in energy between ___ ___ decreases as the distance from the nucleus ___.
shell, ground state, row, energy level, radius, adjacent shells, increases
The angular momentum quantum number tells us the ___ of the orbitals and refers to the ___ that occur within each principle energy level. The greater the value of l, the greater the ___ of the subshell. However, the energies of subshells from different __ __ __ may overlap.
shape, subshells, energy, principle energy levels
The magnetic quantum number describes the ____ of the orbital in space. It specifies the particular orbital within a -__ where an electron is likely to be found at a given point in ___. The ___ and ___ of each orbital are dependent upon the subshell in which the orbital is found
orientation, subshell, time, shape, energy
the spin quantum number defines the intrinsic ___ __ of a particle. Whenever two electrons are in the same ___, they must have opposite spins, and are referred to as ____. Electrons in different orbitals with the same ml values are said to have ___ spins.
angular momentum, orbital, paired, parallel
the rule that subshells are filled from lowest to highest energy and each subshell will fill completely before electrons begin to enter the next one
aufbau principle
_____ rule is used to rank subshells by increasing energy. It states that the lower the sum of the first and second quantum numbers, the ___ the energy of the subshell. If two subshells possess the same value, the value with the lower __ value has lower energy and will fill first
n+l, lower, n
States that within a given subshell, orbitals are filled such that there are a maximum number of half-filled orbitals with parallel spins
hund’s rule
If a material has ___ electrons, a __ __ will align the spins of these electrons and weakly attract the atom to the ___. These materials are said to be ___. Materials that have no ___ electrons and are slightly ____ by a magnetic field are said to be ___.
unpaired, magnetic field, field, paramagnetic, unpaired, repelled, diamagnetic
