Ap Chemistry units 3-4

In atoms and ions, the electrons can be thought of as being in

“shells (energy levels)” and “subshells (sublevels),” as described by the electron configuration

Inner electrons are called

core electrons

outer electrons

valence electrons. 

electron configuration:

1s² 2s² 2p⁶3s² 3p⁶4s² 3d¹⁰ 4p⁶

Isoelectronic

Two elements with the same electronic configuration

When writing the electron configuration for a cation, remove what first? In what first orbitals first?

Remove the valence electrons first...the ones in the p-orbital and s-orbital...then you can remove d-orbital electrons if necessary.

Coulombs Law

Like charges repel and opposite charges attract

Effective Nuclear Charge:

the net positive charge experienced by valence electrons.

Zeff=

total number of electrons - nonvalence elecrons

How to tell if an element has high ionization energy?

Largest ionization lies to the top right of the periodic table

When reading a PES a graph, what do the peaks represent?

The higher the peak, the more electrons in that sublevel

Greater binding energy=

Electrons are closer to the nucleus

Metals are on the ____ side of the zig-zag line and nonmetals are on the ____ side of this line on the periodic table. 

Left , Right

Elements in the same group (vertical columns) have similar…

chemical and physical properties

Moving across a row on the periodic table, the Z_eff

Increases

Moving across a row on the periodic table, the valence electrons

Are more attracted to the nucleus

Moving across a row on the periodic table, the atomic radius ______ and the ionization energy ______.

Decreases , Increases

Atomic radius ______ as you move from left to right across the periodic table

Decreases

The effective nuclear charge _____ from L>R on the periodic table, drawing electrons closer to the nucleus

Increases

Atomic radius ______ as you move _____ a group.

Increases , down

New energy levels are added as you move _____ the group, _____ the atomic radius

Down , Increasing

Ionization energy is

The energy required to remove an electron from an atom

Effective nuclear charge ______ as you move toward the _______

Increases , Right

Ionization energy increases from

L —> R

Ionization energy ______ moving down a row

Decreases

Electrons in a higher energy level are located further from the nucleus and are therefore

Easier to remove

Electronegativity shows

how well an atom can attract electrons towards itself

Electronegativity increases..

L —> R

Electronegativity _____ as you move down a group on the periodic table

Decreases

Why do ionic compounds have high boiling points

Large difference in electronegativities give elements in ionic compounds a strong electrostatic force of attraction.  A large amount of energy is required to break the strong coulombic forces between oppositely charged ions

When an electron is in a higher energy level, it is farther away from the nucleus and therefore has less ______ to the nucleus and is therefore ___________

Coulombic attraction , Easier to remove

Lattice energy is

the energy to break an ionic bond in a compound.

Lattice energy _______ as the ion’s charge _______.

Increases , Increases

Electronegativity:

The tendency of an atom to attract a shared pair of electrons towards itself.

Electronegativity ____ from left to right across a period and _____ down a group

Increases , Decreases

Polarity:

the degree of electron sharing within a molecule

Polar:

Two atoms share electrons unequally

Non polar:

Two atoms share electrons equally

The larger the electronegativity difference (farther apart), the more _______ the bond.

Ionic

atomic radii _____ from left to right across a row and _____ from top to bottom down a column

Decrease , Increase

As you go down the periodic table, atomic size ______

Increases

Increased atomic size = increased _________

atomic length

Hybridization:

the mixing of atomic orbitals into new hybrid orbitals suitable for the pairing of electrons to form chemical bonds / The arrangement of electrons around a central atom.

three main types of hybridization:

sp, sp², and sp³

sp hybridization:

one s and one p orbital hybridizes

Present in atoms with only two regions of electron density

Bond angle of 180

sp² hybridization

one s and two p orbitals hybridize

Present in atoms with three regions of electron density

Bond angle of 120o

sp³ hybridization

one s and three p orbitals hybridize

Present in atoms with four regions of e- density

Bond angle 109.5o

Bond angles:

4 domains =     

3 domains =   

2 domains =

4 = 109.5

3 = 120

2 = 180

Hybrid orbitals:

4 domains =     

3 domains =      

2 domains =

sp³

sp²

sp

Asymmetrical molecules = dipoles DO NOT cancel =

polar molecule

symmetrical = dipoles cancel =

nonpolar molecule

Single bond =  

double bond =   

triple bond =

sigma

sigma + pi bond

sigma + 2 pi bonds

109.5 = sp…

120 = sp…

180 = sp…

sp3

sp2

sp

What can be said about the bond angle in a molecule as more lone pairs are added?

The bond angle decreases

SNAP

Symmetrical

Nonpolar

Asymmetrical

Polar

Formal Charge =

Valence - dots - lines

Lewis Structure & Formal Charge

Obey the octet rule first when drawing the Lewis Dot Structure then use formal charge if necessary.  Extra electrons can go on the larger central atom, and if you have too few electrons, start making some double or triple bonds.

Bond Enthalpy, to break is ___ to form is ___

+ , -

Breaking Bonds is __________

Forming Bonds is __________

Endothermic!  (+) , Exothermic!     (-)

In a chemical reaction: Reactants → Products. You have to break ______

and form ________

reactant bonds (+H, Endo!) , product bonds. (-H, Exo!)

Zeff =

Number of protons - Number of CORE electrons