Chapter 7 Flashcards
Heating and purifying a liquid
Distillation
Taking out by force using different polarities
Extraction
Purifying solids by using differences on solubility
Recrystallization
Separates colored pigments developed by Mikhail Tsvet
Chromatography
Amount of positive charge from the nucleus that has an effect on the selected electron
Effective nuclear charge
Strength of the interaction between two electrical charges depends on the magnitude and distance of the charges
Coulomb’s law of attraction
What doesn’t account for repulsion?
Finding the attraction between electron and nucleus
What does account repulsion?
Effective nuclear charge
Z(eff)= Z - S
Z(eff) = effective nuclear charge Z= atomic number S= # of shielding electrons
What is shielding?
Electrons closer to the nucleus prevent some of the positive charge from reaching the outer valence electrons (electrons in the same subshell do shielding)
Slaters rules
Electrons in the same energy level count as .35 (do not count selected electron)
Electrons in one energy level lower count as .85
All other electrons count as 1.0
S= (x * .35) + (y * .85) + (z * 1.0)
Effective nuclear charge trends
Increases across a period
Increases slightly down a group
The sizes of atoms and ions…
Do not have defined boundaries
Van der waals
Measure distance between two colliding nuclei and divide by two
Bonding atomic radius
Divide distance between nuclei by two
Sizes of atoms trends
Increases going down a column
Decreases going across a period
What does ionic radii depend on
Depends on nuclear charge, number of electrons and the orbital valence electrons reside in
Cations are _____ than parent atoms
Smaller because electrons are removed farthest from the nucleus and electron- electron repulsion is reduced
Anions are ______ than parent atoms
Bigger
Electron-electron repulsion is increased
Isoelectonic series
Group of ions all containing the same number of electrons
Ionization energy
Minimum energy required to remove an electron from an isolated gaseous atom or ion so that the electron and resulting ion are a finite distance apart
First ionization energy
Energy needed to remove the first electron from a neutral atom
Second ionization energy
Energy needed to remove the second electron
Trends for ionization energy
Decreases down groups
Increases across periods
Electron affinity
The change in energy of kJ per mole in a neutral atom while an electron is added to make a negative ion
Why does oxygen require energy to add 2nd electron?
Electrons out number protons, the nucleus does not attract electrons as strongly and the electrons repel eachother
Electron affinity trends
Increases across a period
Decreases down a group
Exceptions to electron affinity rules
Noble gases, group 5 metals and group 2 metals require energy to add an electron because they’re already stable
Metallic character
How closely relatable the element is to the standard properties of a metal
Metallic character trends
Decreases across a period
Increases down a group
Nonmetallic character
How closely relatable the element is to the standard properties of a nonmetal
Metal characteristics
Luster, Solid Malleable and ductile Good conductors Form positive ions Ionic bonding
Nonmetal characteristics
No luster Generally gases Brittle Poor conductors Covalent bonds Negative ions
Metalloids
Elements that have both metal and nonmetal properties
Alkali metal characteristics
Silver luster Behaves as metals High conductivities Low melting and boiling points Reactive (active metals Exothermic Colorless until set on fire
Water as a reactive ion (alkali metals)
Forms hydrogen gas and alkali metal hydroxides
Exothermic reactions
Violent reactions with heavy metals
Oxygen ion as a reactive ion (alkali metals)
Complex reactions
Lithium forms oxides
Sodium forms peroxides
Potassium, rubidium and cesium form superoxides
Alkali metal trends (down group)
Melting point decreases
Densities increase
Become softer
Reactivity increases
Alkaline earth metal characteristics
Solids Metallic properties Melt at higher temperatures Hard and sense Less reactive than 1A Change colors when heated by fire Ca: red Ba: green Sr: bright red Ba: green
Alkaline earth metal trends going down a group
Ease of losing electrons increases
Reactivity increases
Water as a reactive ion (alkaline earth)
Mg reacts with steam
Na and K react with water
Ca reacts with hot water
Forms hydrogen gas and hydroxide
Nonmetals as reactive ions (alkaline earth)
Loses two electrons in a sublevel
Magnesium is least reactive
Heavier= more reactive
Hydrogen characteristics
Colorless, odorless, lowest density
More than double ionization energy compared to other metals, properties of metal and nonmetal
Oxygen group (chalcogens) trends
Melting point, boiling point, ionization energy, electro negativity, density, atomic radius, toxicity and ionic radius increase as you go down
Halogens characteristics
Poor conductors, low melting and boiling points, forms ionic salts, highly reactive, decrease down a group, easily dissociate
Noble gases characteristics
Colorless, monoatomic, large ionization energy, very unreactive, low boiling and melting points
Melting point, boiling point, density and atomic radius increase going down
Balmer spectral lines
Series of spectral lines of the hydrogen atom occur as the electrons transition from higher PEL to lower PEL at a principal quantum number of 2
Balmer equation
Wavelength = R (1/4 - 1/n^2)
R= 1.097* 10^7 m^-1
Paschen spectral lines
Wavelength = R (1/9 - 1/n^2)
Infared
Lyman series
Wavelength = Rh (1/n1^2 - 1/n2^2)
Rh= 1.0974 * 10^-2 nm
Ultraviolet
Paschan
Electrons falling into 3rd PEL
Balmer
Electrons falling into 2nd PEL
Lyman
Electrons falling into 1st PEL
