General Chemistry Chapter 1: Atomic Structure Flashcards
What charge does the proton have?
= to the fundamental unit of charge (e = 1.6 x 10^-19)
What is the atomic number determined by?
The number of protons found in an atom.
What is the difference between atomic number and mass number?
Atomic number = number of protons
Mass number = protons + nuetrons
What are protium, deuterium and tritium?
Isotopes of hydrogen -
Protium = 1 proton
Deuterium = 1 proton + 1 neutron
Tritium = 1 proton + 2 neutrons
What electrons are at the highest energy level?
Highest = furthest away from the nucleus Lowest = closest to the nucleus
Cation vs. Anion
Cation = positively charged atom Anion = negatively charged atom
What is the difference between atomic weight and atomic mass?
Atomic weight = Number reported on the periodic table and is the average of naturally occurring isotopes
Atomic mass = protons + neutrons
How does half-life of an isotope relate to abundance?
Generally, longer half-life = more stable, more abundant
What is avagadro’s number?
6.02 x 10^23 things (ions, atoms, molecules)
Mass is typically written in grams per mole, is the ratio moles to gram also acceptable?
Yes
Who discovered that an atom has a dense, positively charged nucleus?
Ernest Rutherford
Who developed the first quantum theory?
Planck - said that energy emitted as electromagnetic radiation comes in discrete bundles called quanta
Planck relation
E = hf E = energy h = planck's constant (6.626 x 10^-34 Js) f = frequency of radiation
What is the speed of light?
c= 3 x 10^8 m/s
What is the equation for a speed of a wave?
v=f(lambda)
What is the equation that Bohr used to predict the possible values for angular momentum?
L=nh/2(pi)
n=principle quantum number
h=Planck’s constant
What is the equation that Bohr used for the energy of the electron?
E = -R/n^2 R = experimentally determined rydberg unit of energy = 2.18 x 10^-18 J/electron n = quantum number
What is the ground state?
State of lowest energy
What is an atom’s excited state?
When at least one electron has moved to a subshell of higher than normal energy.
As electrons move from a lower energy to a higher energy, they get AHED:
Absorb light
Higher potential
Excited
Distant
When do protons absorb light versus emit?
When going from ground to excited, absorb light.
When going from excited to ground, emit light in the form of photons.
What is the electromagnetic energy equation for photons?
E = hc/lambda
h=Planck’s constant
c=speed of light in a vacuum
lambda = wavelength of light
What is the atomic emission spectrum?
Elements unique finger print of line spectrums which correspond to a specific electron transition.
What is the quantum mechanical model?
electrons do not travel in defined orbits but rather are localized in orbitals
What is an orbital?
An orbital is a region of space around the nucleus defined by the probability of finding an electron in that region of space.
What is the Heisenberg uncertainty principle?
it is impossible to know both an electron’s position and its momentum exactly at the same time
What are the 4 quantum numbers?
n, l, ml and ms
They describe any electron in an atom
What is the principle quantum number?
n = describes the average energy of a shell (1, 2, 3, etc)
What is the auzimuthal quantum number?
l = describes the subshells within a given principle energy level (ranges from 0 to n-1)
What is the magnetic quantum number?
ml specifies the particlar orbital within a subshell where an electron is likely to be found at a given moment in time. (can be integers from +L to -L)
What is the spin quantum number?
ms indicates the spin orientation (either +1/2 or -1/2)
What is Hund’s rule?
subshells with multiple orbitals fill electrons so that every orbital in a subsell gets one electron before any of them gets a second.
What is paramagnetic?
have unpaired electrons that align with magnetic fields, attracting the material to the magnet
What is diamagnetic?
materials have all paired electrons, which cannot easily be realigned, they are repelled by magnets
What is the n + l rule?
The n + l rule says that the lower the sum, the lower the energy of the subshell
