Unit 7: Periodic Properties/Trends Flashcards
What does isoelectronic mean?
ions that posses the same number of electrons, the ion of an element will have the same electron configuration of the closest noble gas
What is a cations size compared to its parent neutral atom?
Cations have a smaller radius than their parent neutral atom
What is a anions size compared to its parent neutral atom?
anions have a larger radius than their parent neutral atom
What is an isoeletronic series?
shows the change in atomic radius due to increasing effective nuclear charge for isoelectronic ions, as teh effective nuclear charge increases the radius decreases (usually placed in decreasing radius order)
What are characteristics for metals?
- silver colored (except gold and copper)
- high luster (shiny!)
- malleable-can be shaped and hammered
- ductile-can be drawn into wires
- conduct heat very well
- conduct electricity well
- exist as solids at room temp (except mercury)
Characteristics of nonmetals
- varied in color (purple iodine, brown bromine, etc)
- lack luster
- brittle
- conduct electricity poorly
- conduct heat poorly
- exist in various phases
Characteristics of metalloids
- a mix of metal properties and non-metal properties
* also called semi-conductors -> moderate conductors of electricity
What did Mendeleev do?
*insisted on grouping by similar characteristics leaving space for undiscovered elements
What did Moseley do?
arranged based on atomic numbers solved some inconsistencies of Mendeleev order
What is ENC? effective nuclear charger
how much pull does the nucleus have on electrons
What is electron shielding?
The non valence electrons protecting the valence electrons from the nucleus
Fill in
The ____ protons= ___ ENC = ____ attraction of electrons
- more
- greater
- greater
What is the equation to find the effective nuclear charge?
Zeff = Z-S zeff = ENC Z= number of protons S= # of core electrons (non valence)
In what trend does ENC increase?
from left to right within a period
In what trend does ENC stay the same?
from top to bottom
What is electron shielding? and what does it do?
the inner electrons (core electrons) act as a barrier between the nucleus and the outer electrons
*limits effect of ENC
What trumps or is more powerful that ENC?
Electron shielding
In what trend does electron shielding stay the same?
across a period
In what trend does electron shielding increase?
down a group
In what trend does atomic radius decrease? and why?
Across a period
*ENC increases while electron shielding stays the same thus pulls the outer electrons in closer
In what trend does radius increase? and why?
moving down within a group
*ENC stays constant, but electron shielding increases. The additional energy levels allow the outer electrons to move farther out
What do groups mean?
Group # = # of electrons (# of electrons in outer shell)
*vertical columns
Which group is halogens?
Noble gases?
alkali metals?
alkali earth metals?
- halogens is group 17
- noble gases is group 18
- alkali metals is group 1
- alkali earth metals is group 2
Definition of ionization energy
the minimum energy required to remove an electron from the ground state of an atom or ion
Fill in
The ____ the ionization energy, the ____it is to take off an electron
- higher
2. harder
In what trend does ionization energy increase? and why?
from left to right (across any row)
*ENC goes up electron shielding stays constant. therefore, more energy is needed to remove an electron
In what trend does ionization energy decrease? and why?
from top to bottom (down any column)
*ENC stays the same, electron shielding goes up. Therefore, less energy is needed to remove an e-
What is electron affinity?
The energy change that occurs when an electron is added to a neutral atom
fill in
the ____ the electron affinity, the _____ the attraction of an atom for an electron
- higher
2. stronger
In what trend does electron affinity increase? and why?
from left to right (across any row) Electron affinity increases
*ENC increases, shield stays the same stronger attractions for e-
In what trend does electron affinity decrease? and why?
from top to bottom (down any column) electron affinity decreases
*ENC stays the same, the shielding goes up. Therefore, slightly harder to gain electrons
