Module 7: Periodic Variations Flashcards
Defined as one-half the distance between the nuclei of two identical atoms when they are joined by a covalent bond
Covalent Radius
Trend in Covalent Raidus
across a period it decreases
down a group it increases
This is the pull exerted on a specific electron by the nucleus taking into account any electron-electron repulsion
Zeff (effective nuclear charge)
formula for Zeff
Z (atomic number) - shielding (core electrons)
trend for Zeff
across a period it increases
determined by the probability of another electron being between the electron of interest and the nucleus as well as by the electron-electron repulsions the electron of interest encounters
Shielding
the measure used to describe the size of an ion
Ionic radius
Trend in Ionic Radii
across a period it decreases
down a group it increases
Is a cation always smaller than its parent atom?
Yes
What happens to Zeff as electrons are removed
Increases
Cations with larger charges are bigger that cations with smaller charges
False
What happens to Zeff as electrons are added
Decreases
Is an anion always smaller than its parent atom?
No
atoms and ions with the same electron configurations
Isoelectronic
For isoelectronic atoms and ions, what determines their size?
the number of protons
What happens to the atomic radius as the nuclear charge increases in a series of isoelectronic atoms and ions?
Decreases
This is the amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state
Ionization Energy
Trend in Ionization Energy
across a period it increases
down a group it decreases
What type of electron is removed when there is a sudden jump in Ionization Energies?
Core Electron
the energy change for the process of adding an electron to a gaseous atom
Electron Affinity
What kind of energy process does negative electron affinity means?
Exothermic (energy is released)
the more negative the EA is the greater its Electron Affinity?
Yes
Trend in Electron Affinity
across a period it increases
down a group it decreases
rows
Periods
it will tell you the highest value of n
Periods
it describes the occupied main energy levels
Periods
it describes the location of the differentiating electron
Group/Family
columns
Group/Family
The electron needed in going from one element to the next in Aufbau Principle
Differentiating Electron
last electron added in the electron configuration
Differentiating Electron
2 ways of assigning groups
US Convention
IUPAC
In US Convention, how to assign Group A and number?
location of differentiating electron is in s or p
then group number is the number of valence electron
In US Convention, how to assign Group B and number?
location of differentiating electron is in d or f
then group number is number of [ns + (n-1)d] electrons
In IUPAC way of assigning group, what is group number if element is in s or p block?
tens digit is 1
unit digit is number of valence electrons
In IUPAC way of assigning group, what is group number if element is in d block?
group number is equal to number of [ns + (n-1)d] electrons
Trend in atomic size
across a period it decreases
down a group it increases
Trend in metallic property
across a period it decreases
down a group it increases
What happen to atomic size and Zeff when valence electrons increases?
atomic size decreases
Zeff increases
Trend in electronegativity
across a period increases
down a group decreases
elements with the greatest electronegativity
Fluorine
Oxygen
Nitrogen
