MCAT

• In element notation, A is the Mass number
• In element notation, Z is the atomic number
• Atomic weight is the weighted average of the masses of an element's isotopes Each mass is multiplied by the isotope's natural abundance
• The Rutherford Model states that an atom is mostly empty space, with electrons orbiting a fixed, positively charged nucleus
• According to the Bohr Model, electrons orbit the nucleus in orbits that have a set size and energy
• The Heisenberg Uncertainty Principle states that it is impossible to know the momentum and position of an electron simultaneously
• Hund’s Rule states that all orbitals must first have one electron before any orbital can obtain a second electron
• The Pauli Exclusion Principle states that no two electrons can share the same four identical quantum numbers That means, for paired electrons, one must be +1/2 spin and the other -1/2 spin
• Avogadro’s Number = 6.022 × 1023 = 1 mol
• Planck’s Constant (h) = 6.626 × 10-34 J•s
• Speed of Light (c) = 3.0 × 108 m/s
• Give the equation for energy of a photon: E = energy of a photonh = Planck’s Constant c = speed of light λ = wavelength f = photon frequency
• Diamagnetic materials are repelled by an external magnetic field All electrons are paired and have opposing spins ↑↓
• Paramagnetic materials are pulled into an external magnetic field Contain one or more unpaired electrons with spin ↑
• He is diamagnetic
• Li is paramagnetic
• Quantum number n is the principal quantum number and gives the electron energy level or shell number "1, 2, 3, ... Except for d- and f-orbitals, the shell # matches the row of the periodic table Khan Academy Link"
• Quantum number l is the azimuthal quantum number and gives the 3D shape (subshell) of an orbital 0, 1, 2, …, n-1 0 = s orbital 1 = p orbital 2 = d orbital 3 = f orbital 4 = g orbital
• Quantum number ml is the magnetic quantum number and gives the orbital sub-type Integers -l to +l The orientation of the electron's orbital with respect to the three axes in space, x, y, and z.
• Quantum number ms is the spin quantum number and gives the electronic spin of the electron +1/2 or -1/2
• The maximum number of electrons in a single energy level in terms of principal quantum number = 2n2 Example: What is the maximum number of electrons that can be in the second energy level? 2n2 = 2(22) = 8 electrons
• The maximum number of electrons in a single subshell in terms of the azimuthal quantum number = 4l + 2 The number of orbitals in a subshell = 2l + 1 With a maximum of 2 electrons per orbital, the maximum number of electrons per subshell = 2(2l + 1) = 4l + 2 Example: For the d subshell, we know the mathematical value for d is l = 2 4l + 2 = 4(2) + 2 = 10 electrons at maximum in the d subshell
• A/an free radical is an atom or molecule with an unpaired electron
• The Azimuthal quantum number for this orbital is 0 = s orbital
• The Azimuthal quantum number for this orbital is 1 = p orbital
• The Azimuthal quantum number for this orbital is 2 = d orbital
• The Azimuthal quantum number for this orbital is 3 = f orbital
• Give the principal and azimuthal quantum number labels for the periodic table Principal (n) quantum number = 1, 2, 3, ... Azimuthal (l) quantum number = 0, 1, 2, …, n-1
• The Aufbau Principle states that electrons will fill the lower energy levels before moving to higher energy orbitals
• The elements in the group labeled with ? are known as alkali metals
• The elements in the group labeled with ? are known as alkaline earth metals
• The elements in the groups labeled with ? are known as transition metals
• The elements in the group labeled with ? are known as post-transition metals
• The elements in the group labeled with ? are known as metalloids
• The elements in the groups labeled with ? are known as non-metals
• The elements in the group labeled with ? are known as halogens
• The elements in the group labeled with ? are known as noble gases
• The elements in the groups labeled with ? are known as rare earth metals Lanthanides and Actinides
• Zeff is the attractive positive charge of nuclear protons acting on valence electrons Zeff is always less than the total number of protons present in a nucleus due to the shielding effect from other electrons in the atom
• What is the periodic trend for effective nuclear charge?