Chem Exam III (Ch. 3,4,5)

Zeff

effective nuclear charge is defined as the net positive charge pulling these electrons towards the nucleus; Zeff = number or protons - shielding amount

left to right

What is the general trend of Zeff?

1) write long form e- configuration
2) identify e- of interest
3) look at numbers of e- of interest then multiple by 0.35
4) find one shell less of e- of interest then multiply by 0.85
5) find any shell at least two less than e- of interest an multiply by 1

What are the steps of Slater's rules?

Slater's rules

provide numerical values for the effective nuclear charge in a many-electron atom

Van der waals

touching atoms are not bonded

covalent radius

bond formed between like atoms a

atomic radius

take the average in a bunch of compounds; the exact value depends on compound it is measured in

right to left and top to bottom

What are the trends of atomic radius?

cations

these lose electrons so the remaining experience greater zeff so overall size will decrease

anions

these add electrons so the remaining experience lowers zeff (more shielding), so overall size increases

isoelectronic series

several same number electrons, but different protons; the more positive it is the smaller the atom and the more negative the larger

ionization energy

the amount of energy required to full remove an electron from a species ex: X(g) -> X+ (g) + 1e-

left to right and bottom to top

What are the trends for ionization energy?

decrease, increase

Increasing shielding will _____ IE, and as charge increases IE ______

Group 16 has lower IE than expected, and group 13 removes the 1st p electron

What are the two exceptions to the ionization trend?

electron affinity

this is the energy released when an electron is added to an atom (negative values) [ X(g) + 1e- -> X (g) ]

left to right and bottom to top

What are the trends for electron affinity?

group two has lower EA than expected and group 14 is more negative than group 15

What are the two exceptions of electron affinity?

lower left

What location has the largest atomic radius?

metallic character

this is how much something acts/ has the characteristics as a metal

compounds

any substance composed of identical molecules consisting of atoms of two or more chemical elements

chemical bonds

a bond that holds atoms together. It is the force that binds ions or molecules together.

decrease

When bonds form energy _____ which is favorable.

ionic bonds

this bond is formed between a metal and nonmetal (or polyatomic atoms); electrons are transferred from the metals to nonmetals

cation

What kind of ion do metals form?

anion

What kind of ion do nonmetals form?

electrostatic

What kind of interaction are between opposite species?

salt

What is another name for ionic compounds?

lattice network

This is a network that consists of all ions that balance out charges

covalent bonds

these bonds are formed between nonmetals; they form molecules and electrons are shared between atoms

chemical formulas

notation used by scientists to show the number and type of atoms present in a molecule, using the atomic symbols and numerical subscripts.

empirical formula

the lowest whole number ratio; how ionic compounds are always given

molecular formula

these provide exactly how many of each atom per molecule; only different from empirical formula for some covalent compounds

structural formula

provides a bit more information about how the atoms are linked

lewis dot structure

A way of representing atoms or molecules by showing electrons as dots surrounding the element symbol.

octet rule

this is when atoms prefer s & p shells filled; atoms want 8e- around the outside

1) find how many valence electrons
2) show each electron as a dot
3) then add the dots around

What are the steps of the lewis dot symbol structures?

solids

Are ionic compounds typically solids, liquids or gases?

electrolytes

Ionic properties act as _____ when dissolved in H2O

all

Are ionic compounds typically solids, liquids or gases?

polyatomic ions

this is a group of covalently bound atoms which has an overall charge; they act as the anion or cation in the ionic compound

oxyanions

species with oxygen in them; have their own naming system

family of polyatomics

these have the same charges but different numbers of oxygen

hydrates

any compound containing water in the form of H2O molecules

anhydrous

compound with no water

diatomics

contain two atoms that are chemically bonded (often the same atom like O2)

formula mass

the molecular mass; the sum of the atomic weights of atoms in a molecule.

mass % composition

this is based on the law of definite proportions -> % of each element is constant for a given compound

combustion analysis

a standard method of determining a chemical formula of a substance that contains hydrogen and carbon

methane

CH4

ethan

C2H6

methanol

CH3OH

ethanol

C2H5OH

ethene

C2H4

ethyne

C2H2

bond polarity

The distribution of electrical charge over the atoms connected by the bond is referred to as polarity in chemical bonding.

polarity

this is a measure of how unequally electrons are shared within a bond

nonpolar covalent

a type of chemical bond that is formed when electrons are shared almost equally between two atoms

polar covalent

covalent bond in which the electron density is unevenly shared between the two bonded atoms, due to a difference in electronegativity or due to inductive effects.

ionic character

this measures the ionic compound sharing

formal charge

this helps us figure out and find the most favorable structure

resonance structures

these provide completely equivalent options for multiple bonds

free radicals, incomplete octets, expanded octets

What are the three octet rule exceptions?

free radicals

total of valence electrons is an add number

incomplete octet

molecule or polyatomic ions where an atom has less than an octet

expanded octet

this helps to minimize the formal charge

bond order

the number of bonding pairs of electrons between two atoms

bond energies

how much energy is needed to break the bond (all endothermic (+))

bond lengths

the average distance between nuclei of two bonded atoms in a molecule.

VSEPR

What is used to show the 3-dimensional shape of compounds?

linear, trigonal planar, tetrahedral, trigonal bipyramidal, octahedral

What are the 5 electron domain geometries?

linear

What electron domain geometry?:
- 2e- domains

trigonal planar

What electron domain geometry?:
- 3e- domains

tetrahedral

What electron domain geometry? :
- 4e- domains

trigonal bypyramidal

What electron domain geometry? :
- 5 e- domains

octahedral

What electron domain geometry?:
- 6 e- domains

linear

What is the molecular geometry name when there is 2 electron domains and 0 lone pairs?

trigonal planar

What is the molecular geometry name when there is 3 electron domains and 0 lone pairs?

bent

What is the molecular geometry name when there is 3 electron domains and 1 lone pair?

tetrahedral

What is the molecular geometry name when there is 4 electron domains and 0 lone pairs?

trigonal pyramidal

What is the molecular geometry name when there is 4 electron domains and 1 lone pairs?

bent

What is the molecular geometry name when there is 4 electron domains and 2 lone pairs?

trigonal bypyramidal

What is the molecular geometry name when there is 5 electron domains and 0 lone pairs?

seesaw

What is the molecular geometry name when there is 5 electron domains and 1 lone pairs?

t-shape

What is the molecular geometry name when there is 5 electron domains and 2 lone pairs?

linear

What is the molecular geometry name when there is 5 electron domains and 3 lone pairs?

octahedral

What is the molecular geometry name when there is 6 electron domains and 0 lone pairs?

square pyramid

What is the molecular geometry name when there is 6 electron domains and 1 lone pair?

square planar

What is the molecular geometry name when there is 6 electron domains and 2 lone pairs?

t-shape

What is the molecular geometry name when there is 6 electron domains and 3 lone pairs?

linear

What is the molecular geometry name when there is 6 electron domains and 4 lone pairs?

180 degrees

What is the bond angle of linear molecular geometry?

120 degrees

What is the bond angle of trigonal planar molecular geometry?

What is the bond angle of bent molecular geometry for the trigonal planar edg?

109.5 degrees

What is the bond angle of tetrahedral molecular geometry?

What is the bond angle of trigonal pyramid molecular geometry?

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What is the bond angle of bent molecular geometry for the tetrahedral edg?

120 and 90 degrees

What is the bond angle of trigonal bipyramid molecular geometry?

What is the bond angle of seesaw molecular geometry?

What is the bond angle of t-shape molecular geometry of the trigonal bipyramidal edg?