Atomic Structure & Periodic Trends Flashcards
What is the Molarity (M) formula?
moles of solute/liters of solution = mol/L
What is the molality (m) formula?
moles of solute/kilograms of solvent = mol/kg
What is electronegativity?
the tendency for an atom to attract a bonding pair of electrons. Electronegativity unlike other periodic trends is measured within a bond.
What does Zeff stand for?
Effective nuclear charge
Zeff is the net positive charge pulling these electrons towards the nucleus. The stronger the pull on the outermost electrons (valence electrons) towards the nucleus, the higher the effective nuclear charge.
What is the effect of Zeff on periodic trends?
What does higher Zeff correlate with on the periodic table?
The greater the effective nuclear charge the greater the electronegativity
Effective nuclear charge depends on the number of protons in the nucleus, the distance from the nucleus, and the amount of shielding by inner shell electrons. The number of protons increases Zeff , while the distance and amount of shielding decreases Zeff
True or False: Zeff depends on the attraction of the bonding pair towards the nucleus
False
Effective nuclear charge depends on the number of protons in the nucleus, the distance from the nucleus, and the amount of shielding by inner shell electrons. The number of protons increases Zeff , while the distance and amount of shielding decreases Zeff
The atomic number is represented by the letter…
Z
the # of protons = Z
The mass number is represented by the letter…
A
the # of protons + neutrons = A
Group 1 of the periodic table is…
alkali metals
What are characteristics of alkali metals?
- distinctive flame colors
- good electrical conductors
- solid under standard conditions
- shiny or lustrous
- ductile (can be easily stretched into wires)
- malleable (can be made into shapes/sheets)
- very reactive!
mercury is the exception to the solidity characteristic
alkali metals have lone valence electrons making them incredibly reactive
Group 2 of the periodic table
Alkaline earth metals
What are characteristics of alkaline earth metals?
- metallic character
- reactive
- good conductors
- oxidation state of 2+
they also form hydroxides when they react with water
What are characteristics of transition metals?
- lusterous
- hard & durable
- good conductors
- take on vivid colors due to electronic transitions between D orbitals
- multiple oxidation states
characterized by many oxidation states due to the low reactivity of the unpaired d electrons
What are characteristics of non-metals?
- not shiny/lustrous
- poor conductors
What are the characteristics of metalloids
also known as semimetals
they share the characteristics of metals and non-metals
* brittle
* poor to decent conductors
* act like nonmetals in chemical reactions, but can vary
Boron and Silicon are the ones you will most likely see on the MCAT
Chalcogens are
what group #? What elements?
Group 16, include oxygen and sulfur
have nearly filled valence shells
What is group 17 of the periodic table?
Halogens
F, Cl, Br, I
have nearly filled valence shells and are very reactive, especially with alkali metals
What is the effect of Zeff on periodic trends?
What does higher Zeff correlate with on the periodic table?
The greater the effective nuclear charge the greater the electronegativity
Effective nuclear charge depends on the number of protons in the nucleus, the distance from the nucleus, and the amount of shielding by inner shell electrons. The number of protons increases Zeff , while the distance and amount of shielding decreases Zeff
Describe the relationship between transition metals and ionization energy
transition metals have little variability in their ionization energies and electronegativities due to their similar valence electron shells, which is the s shell
What is the relationship between reactivity and oxidation states
High reactivity would limits the number of oxidation states
The amount of energy required to remove an electron from an isolated atom or molecule is….
ionization energy
the energy change that results from adding an electron to a gaseous atom
electron affinity
What periodic aligns with the radius of an atom decreasing from left to right across a period as more protons and electrons are added?
atomic radius (also called atomic size)
______, _____ and _____ periodic trends increase diagonally from bottom left to top right
Ionization energy, electron affinity, and electronegativity
E = hf represents …
What does each variable stand for? What does the equation quantify?
Electromagnetic radiation
E = energy of electromagnetic radiation
h = Plank’s constant
f = frequency of light
What are the units of the frequency of light (f) ?
3.00 x 108 m/s
True or False
Electromagnetic radiation includes the full continuum of light
True!
This radiation encapsulates full continuum of wavelengths
Think of everything from visible light to gamma waves to X-rays!
E = hc/ƛ represents….
What does it quantify? What do the variables represent?
The energy of a photon
This equation is equal to the electromagnetic radiation formula E=hf !
True or false
Each element has an absorption and emission sprectrum
True!
Since energy is aborrbed and released in quanta, the absorption or emission of electromagnetic radiation results in a caracteristic absorption and emission spectrum that are unique for each element
Name the equation
What does it represent?
The Rydberg formula
Used to predict the wavelength of light resulting from an electron moving between energy levels of an atom
What does this equation represent?
Eqn 4. pg. 6 NS
Energy change (in Joules) of an electron moving between energy levels
Modified Rydberg equation
(+) ΔE means that energy is ____ and - ΔE means that energy is _____
absorbed, released
Define the term
Posits that we cannot simultaneously know the exact position and the momentum of a given electron
Heisenberg uncertainty principle
Denotes the energy level of an electron
Corresponds to the Bohr radii
Hint: represented by n
principle quantum number
the higher the n value, the greater the energy, and thus the further the distance from the nucleus
The periodic table is arranged in rows corresponding to…
Bohr radii; n
i.e Sodium is in the 3rd period, and this element has a principal quantum number of n=3
What quantum number describes the shape of an orbital’s subshell?
Give the letter and the name
angular momentum quantum number (l)
azithmul quantum number
note: there is 1 s orbital, 3 p orbitals, 5 d orbitals, and 7 f orbitals
Which quantum number describes the spatial orientation of the orbital region of space with respect to an applied magnetic field?
magnetic quantum number ml
described in integers of -l to +l
What quantum number describes the spin orientation of the electron in an external magnetic field?
spin quantum number ms
the two spin orientations are ms = +1/2 (up) or -1/2 (down). Note that because of spin orientations, an s orbital can have up to 2 electrons, p orbitals 6 electrons, d can have 10, and f can have 14
Name the principle/rule:
every orbital in a sublevel is singly occupied before any orbital is doubly occupied
Hund’s rule
Name the principle/rule:
electrons are filled into atomic orbitals in the increasing order of orbital energy level
Aufbau principle
Name the principle/rule:
No two electrons can have the same quantum numbers
Pauli exclusion principle
