Chapter 1 Atomic Structure Flashcards
What are the three subatomic particles and what are their charges?
protons- positive (+1/+1e)
neutrons- neutral
electrons- negative (-1/-1e)
e = 1.6x10-19C
Where are protons found, and what is their mass?
Protons are found in the nucleus, and they are approximately 1 AMU (atomic mass unit)
What does the atomic number of an element refer to? How does atomic number change between isotopes?
The atomic number of an element refers to the number of protons an element has.
Isotopes are elements with the same number of protons, but they vary in NEUTRONS, thus the atomic number does not change between isotopes.
What is an element’s mass number?
An element’s mass number is the sum of the protons and neutrons in an atom’s nucleus.
What are isotopes?
Isotopes are atoms that share an atomic number (number of protons) but have different mass numbers.
Number of neutrons varies between isotopes but the number of protons remains constant.
What does each letter represent?
X: atom/element
A: Mass number of atom X
Z: atomic number
Mass number v Atomic Number
Mass number: sum of protons and neutrons in an atom’s nucleus; varies between isotopes
Atomic number: sum of atom’s protons; constant between isotopes
Where do electrons move and what are they associated with?
Electrons move through the same surrounding the nucleus, and they are associated with varying levels of energy
How does the distance of an electron from the nucleus impact its energy level?
Electrons closer to the nucleus are at lower energy levels
Electrons that are farther from the nucleus are at higher energy levels.
What are valence electrons, and what are they more likely to do and why?
Valence electrons are electrons that are farthest from the nucleus. They have the strongest interactions with the surrounding environment and the weakest interactions with the nucleus.
Valence electrons are more likely to become involved in bonds with other atoms because they experience the least electrostatic pull from their own nucleus.
Losing electrons results in the atom gaining a ___ charge.
Gaining electrons results in the atom gaining a ___ charge.
Losing electrons results in the atom gaining a positive charge.
Gaining electrons results in the atom gaining a negative charge.
What is a cation?
What is an anion?
A cation is a positively charged atom.
An anion is a negatively charged atom.
Atomic mass v atomic weight
The atomic mass of an atom is nearly equal to its mass number (sum of protons and neutrons in an atom’s nucleus)
The atomic weight is the weighted average if different isotopes, and it is the number reported on the periodic table.
What is the Planck relation (equation), and what does it provide?
Planck relation: E = hf (where h = 6.626x10-34 J *s)
h = Planck’s constant; f is the frequency of radiation
This describes the energy of a quantum
Ground state v Excited State
Ground State of an atom: the state of lowest energy, in which all electrons are in the lowest possible orbital
Excited State: an atom is an excited state when at least one electron has moved to a subshell of higher than normal energy
What is the most significant difference between the Bohr Model and the Modern Quantum Mechanical Model
Bohr postulated that electrons follow a clearly defined circular pathway (orbit) at a fixed distance from the nucleus. Modern Quantum Mechanics shows that this is not the case; electrons are localized in orbitals (regions of space around the nucleus)
What does the Heinsenberg Uncertainty Principle state?
It is impossible to simultaneously determine, with perfect accuracy, the momentum and position of an electron
What does Hund’s Rule state?
Orbitals fill according Hund’s rule
Hund’s rule states that there are a max number of half-filled orbitals with parallel spins
half-filled and fully filled orbitals have lower energies (and thus higher stabilities) than other states
