Chemistry Chapter 5
Why did Bohr's model fail?
It failed to explain the spectrum for elements other than hydrogen
Werner Heisenberg
It is impossible to take any measurement of an object without disturbing the object
What is the difference between an atom's ground state and an excited state?
The difference between an atom's ground state and an excited state is that the ground state is the lowest energy level and an excited state is any energy level that is not the ground state and has more energy than the ground state.
According to the Bohr model, how do electrons move in atoms?
The electrons move in circular orbits around the nucleus.
What is the maximum number of electrons an orbital can contain?
The maximum number of electrons an orbital can contain is 2 electrons.
What does n represent in the quantum mechanical model of the atom?
The n in the quantum mechanical model of the atom represents the size and energy of an orbital.
What is the name of the atomic model in which electrons are treated as waves? Who first wrote the electron wave equations that led to this model?
The name of the atomic model in which electrons are treated as waves is the Quantum Mechanical Model of the atom and the person who wrote the electron wave equations is Erwin Schrödinger
Quantum Number
The number assigned to each orbit of an electron. orbit increases as quantum number increases
Describe the relative orientations of the orbitals related to an atom's 2p sublevel.
The relative orientations of the orbitals in an atom's 2p sublevel is 3 orbitals, 2px, 2py and 2pz that look like figure eights and are perpendicular to each other
What are valence electrons? How many of a magnesium atom's 12 electrons are valence electrons?
Valence electrons are electrons on the outermost orbital. A magnesium atom has 2 valence electrons.
noble gas configuration for Vanadium
[Ar] 4s23d2
Use noble-gas notation to describe the electron configurations of the elements represented by the following symbols. a. Kr b. P c. Zr d. Pb
[Ar]4s2 3d10 4p6, [Ne]3s2 3p3, [Kr]5s2 4d2, [Xe]6s2 4f14 5d10 6p2.
Atomic Orbital
a 3D region around the nucleus of an atom that describes an electron's probable location. density at a given point is proportional to the probability of finding the electron at that point. no boundary/exact size
Pauli exclusion principle
a maximum of two electrons can occupy a single atomic orbital, only if they have opposite spins
De Broglie Equation
all moving particles have wave characteristics
three rules that determine electron configuration
aufbau principle, pauli exclusion principle and hund's rule
Which element could have the ground-state electron-dot notation shown? a. manganese b. antimony • • c. calcium • X • d. samarium •
b. antimony
aufbau principle
each electron occupies the lowest energy orbital available.
valence electrons
electrons in an atoms outermost orbitals determine chemical properties of an atom
electron-dot structure
element's symbol, surrounded by dots representing valence electrons
Heisenberg uncertainty principle
it is fundamentally impossible to know precisely both the velocity and position of a particle at the same time. fundamental limitations of what can be observed. uncertainty of position = 10^-9 m
principal quantum number
n, indicates the relative size and energy of atomic orbitals. as orbital increases, electron spends more time farther from nucleus. lowest level is n = 1.
Hund's rule
single electrons with the same spin must occupy each equal energy orbital before more electrons with opposite spins can occupy the same orbitals
electron configuration
the arrangement of electrons in an atom, prescribed by 3 rules.
Quantum mechanical model of the atom
the atomic model in which electrons as treated as waves. the wave mechanical model of the atom. Erwin Schrödinger. makes no attempt to describe electron path around nucleus
energy sublevels
the energy levels contained within an principal energy level increases with n. labeled s, p, d or f based on shape of atomic orbitals
Ground state of an electron
the lowest allowable energy state of an atom. does not radiate energy
principal energy level
the major energy levels of an atom
particle electromagnetic-wave relationship
wavelength = planck's constant/ (mass of particle x velocity)
Excited state of an electron
when an atom gains energy
Draw an electron-dot structure for an atom of each element. a. carbon b. arsenic c. polonium d. potassium e. barium
• •• •• •C• • As • : Po • K• • Ba • • • •
What is an atomic orbital?
An atomic orbital is the three dimensional region surrounding the nucleus where electrons are probably located.
explain why one electron in a rubidium atom occupies a 5s orbital rather than a 4d or 4f orbital.
Because there is less energy in 5s there than there is in 4d or 4f.
Which electron configuration notation describes an atom in an excited state? a. [Ar]4s^ 2 3d^ 10 4p^ 2 b. [Ne]3s ^2 3p^ 5 c. [Kr]5s ^2 4d ^1 d. [Ar]4s ^2 3d ^8 4p ^1
D
Louis de Broglie
Fixed Bohr's model, asked, "can particles of matter behave like waves?"
What element is represented by each electron configuration? a. 1s^ 2 2s^ 2 2p ^5 b. [Ar]4s^ 2 c. [Xe]6s^ 2 4f ^4 d. [Kr]5s^ 2 4d ^10 5p ^4 e. [Rn]7s^ 2 5f ^13 f. 1s^ 2 2s^ 2 2p ^6 3s ^2 3p ^6 4s ^2 3d ^10 4p^ 5
Fluorine, Calcium, Neodymium, Tellurium, Mendelevium, Bromine
Who was Neils Bohr?
He proposed a quantum model for the hydrgen atom that found why the atomic emission spectra of elements is discontininuous. later proved incorrect
name the order of energy levels up to 7p
1s 2s 2p 3s 3p 4s 3s 4p 5s 4d 5p 6s 4f 5d 6p 6s 5f 6d 7p
Write each element's orbital notation and complete electron configuration. a. beryllium b. aluminum c. nitrogen d. sodium
1s2 2s2, 1s2 2s2 2p6 3s2 3p1, 1s2 2s2 2p3, 1s2 2s2 2p6 3s1.
configuration for Oxygen
1s22s22p4
configuration for Silicon
1s22s22p63s23p2
configuration and dot diagram for: Iodine
1s22s22p63s23p64s23d(10)4p65s24d(10)5p5 • • • I : • •
configuration for Manganese
1s22s22p63s23p64s23d5
