Ch 24 Flashcards
Dalton’s atomic theory states:
- All elements are composed of atoms
- All compounds are made of atoms from various elements
- Atoms can’t be created / destroyed in chemical reactions
One amu is equivalent to
One dalton
The atomic number of an element is equal to
Number of protons, which is the same as the number of electrons
What are isotopes?
Different number of neutrons found in the same element
The mass number of an element is equal to
Total number of protons and neutrons
What is Avogadro’s number?
6.02 * 10^23
Who provided experimental evidence that an atom has a dense, positively charged nucleus?
Ernest Rutherford
Who developed the first quantum theory?
Max Planck
What does the quantum theory state
Matter emits energy as electromagnetic radiation in bundles called “quanta”
The energy value of a quantum is given by
E = hf
What is the value of h?
6.662 * 10^-34
What is the energy of an electron according to the Bohr Model?
E = -RH / n^2
How is the energy of an electron related to its orbital radius?
The smaller the radius, the lower the energy state of the electron
The Bohr model is used to explain the
Atomic emission spectrum and atomic absorption spectrum
Electrons can be excited to higher energy levels via
Heat or other energy
Electrons rapidly return to the ground state because
The lifetime of the excited state is brief
The electromagnetic energy of photons is described using what equation?
E = hc / wavelength
When electrons return to their ground states, each electron emits a
Photon with the wavelength characteristic of the specific transition it undergoes
What is a line spectrum?
Each line on a spectrum corresponds to a specific electron transition
Why does each element possess a unique atomic emission spectrum?
Each element can have its electrons excited to different energy levels
Describe the Lyman Series?
n = 1, UV spectrum
Describe the Balmer Series?
n = 2, Visible and UV spectrum
Describe the Paschen Series?
n = 3, Infrared spectrum
Describe Energy between higher and lower energy:
E = -Rh (1/ni^2 - 1/nf^2)
Absorption is when
Electron jumps to a higher energy level
Emission is when
Electron lowers to a lower energy level
The excitation of electrons results in
Energy absorption
What can be used to identify elements present in a gas phase sample?
Absorption spectra
What is the Heisenberg uncertainty principle?
States that it is impossible to determine BOTH the momentum and position of an electron
According to the Pauli exclusion principle
No two electrons possess the same set of quantum numbers
What is an electron’s energy state?
The position and energy of an electron via its quantum numbers
The principle quantum number (n) gives information about the orbital’s
Size
The angular quantum number (l) gives information about the orbital’s
Shape
The magnetic quantum number (ml) gives information about the orbital’s
Orientation
The principle quantum number (n) represents
The shell where an electron is present in an atom
The maximum n corresponds wit the element’s
Period in the table
The larger the value of n, the
Higher the energy level and radius of electron’s orbit
What is the maximum number of electrons in an electron shell?
2n^2
How is the energy in between adjacent cells as the distance from the nucleus increases?
The energy decreases as the distance increases
The angular quantum number (l) tells us both the shape of the orbitals and refers to
The subshells that occur within each principle energy number
When l = 0, what is the subshell?
S
When l = 1, what is the subshell?
P
When l = 2, what is the subshell?
D
When l = 3, what is the subshell?
F
The maximum number of electrons found in a subshell can be given by the equation of
4l + 2
