Chapter 9 Flashcards
What are degenerate orbitals?
orbitals that have same energy. Think of how p has 3 different orbitals in same energy
Aufbau’s Principle
fill up lower energy levels with electrons first
Hund’s rule
When adding electrons in degenerate orbitals, add electrons one at a time with parallel spins
What are the main group elements?
Elements in group 1, group 2, and groups 13-18
What are valence electrons?
electrons most important in chemical bonding
Where are valence electrons for main group elements?
Valence electrons are those in the outermost principal energy level
Where are the transition elements on the periodic table?
Elements found in groups 3-12
Starts with Sc, ends with Zn
What is different about valence electrons for transition elements?
The outermost d electrons are counted as valence with the outermost principal energy level electrons
chemical properties of an element depend on what?
Its valence electrons, they are held most loosely so they are the easiest to loose/share
Why do elements in a column of the periodic table have similar chemical properities?
They have the same number of valence electrons
The other electrons in an atom (other than valence) are called what?
core electrons
Where is the s-block on the periodic table?
First two columns on the left side with Helium (HE) on the right
Where is the p block on the periodic table?
First six columns on the right excluding He, made up of halogens and nobel gases
Where is the d block on the periodic table?
starts after s block elements on the left (3rd column) to 12th column on right before p block elements
Where are the f-block elements?
2 rows at the bottom
number of columns in a block corresponds to the maximum what?
number of electrons that can occupy the particular sublevel of that block
ex: s block has two columns bc 1 s orbital can hold two electrons
p block has 6 columns bc 3 p orbitals with 2 electrons each
d block has 10 columns corresponding to 5 d orbitsld with two electrons each
the number of valence electrons in main-group element is equal to
its lettered group number
ex: chlorine has 7 valence electrons because its in group 7A
the row number in the periodic table is equal to
the highest occupied principal level
ex: chlorine in row 3, highest principal level is n=3 level
van der Waals radius
atomic radius determined by the distance between nonbonding atoms in direct contact
What is bonding atomic radius or covalent radius?
nonmetals: 1/2 the distance between two atoms bonded together
metals: 1/2 the distance between two of the atoms next to eachother in a crystal or metal
what is atomic radius?
set of average bonding radii determines from measurements on a large number of elements or compounds
How are atomic radius and van der Wall radius different?
atomic radius represents the radius on an atom when it is bonded to another atom and is always smaller than van der Waal
What is the bond length of two covalently bonded atoms?
sum of their atomic radii
What are the two general trends on periodic table for van der Waals radii?
- As we move down a column in periodic table, atomic radius increases
- As we move to the right across a period (row) atomic radius decreases
The atomic radius decreasing as you go to the right is caused by what?
inward pull of electrons in outermost principal energy level
what is the effective nuclear charge?
the average or net charge experienced by an electron
What is equation for effective nuclear charge?
Zeff = Z (actual nuclear charge)-S (charge screened by other electrons)
What is shielding?
Repulsive force exerted on valence electrons by core electrons
what increases the shielding effect?
more core electrons
What are some effects of the shielding effect?
atomic radius increases (electrons pushed out), Ionization energy decreases (electrons are easier to add/drop when further away), and electronegativity decreases (electrons aren’t as close to nucleus)
How to find greatest shielding energy?
elements with the most electrons
What are the two different types of shielding?
-shielding of the outermost electrons by the core electrons and shielding of the outermost electrons by eachother
core electrons shield electrons in outermost principal energy level from what?
nuclear charge. Outermost electrons don’t shield eachother from nuclear charge
What is the different trend for transition elements?
they stay roughly constant across each row, because the number of electrons in the outermost principal energy level is nearlt constant
What is penetration?
Ability of an electron in a given subshell to penetrate within other shells and get close to the nucleus
What does this graph show?
Radial probabilty function
-shows penetration in individual orbitals
paramagnetic vs diamagnetic
paramegnetic have unpaired electrons, diamagnetic only have paired electrons
