Ch.2 Bonding and Intermolecular forces Flashcards
What is a molecule?
any structure composed of multiple atoms
What is a compound?
a molecule that has atoms of more than one element connected together
When discussing nomenclature, how do you name binary compounds?
Ionic compounds - list cation first, then Anion second
Molecular compound - Arrange in order of electronegativity. (exception list carbon first, hydrogen after nitrogen)
Prefixes and suffixes are used in molecular compounds
What is an Ionic compound?
A metal and nonmetal molecule
What is a molecular compound?
It contains 2 nonmetals
In Ionic compounds why is it important that metal is identified with roman numerals?
Because it shows the oxidation state.
This allows us to determine how many electrons are being shared with another atom.
Forces that hold atoms together within a molecule are called?
Intramolecular forces
Forces that determine how molecules interact with each other are?
Intermolecular forces
What are the various types of Intramolecular forces?
Covalent, Ionic, and Metallic bonds
What is a covalent bond?
a bond formed between 2 nonmetals, by sharing valence electrons.
(they share electrons because their electronegativity lvl is similar)
What is a nonpolar covalent bond?
An element with the same (or similar) electronegativity are bonded together.
What is a polar covalent bond?
Atoms with a moderate difference in electronegativity are bonded together.
Covalent bonds have 2 different electronegativity values, what are they?
< .5 = nonpolar
.5 - 1.7 = polar
(greater than 1.7 = Ioninc bonds)
Since polar molecules unequally share electrons, a stable dipole forms. What is a dipole?
A dipole is a depiction of the vector of shared electrons.
A line with a plus is drawn.
What is an Ionic bond?
A complete transfer of one or more valence electrons (electronegativity must be >1.7).
Ionic bonding occurs between metal and nonmetal, and is stronger than covalent bonding.
Which is stronger covalent or Ionic?
Ionic bonding
Which type of force is stronger, intramolecular or intermolecular?
Intramolecular
What are the types of intermolecular bonding
London dispersion Dipole-dipole Hydrogen Ion-dipole Ionic interactions (in order from least to greatest)
What is a London dispersion force?
Occur when temporary dipoles arise by chance
larger structure will have a greater force
What is a Dipole-dipole interaction?
Occur between polar molecules.
It is a attractive force that occurs between the positive dipole of one polar molecule and the negative dipole of another.
Explain hydrogen bonding
It is not true bonding
When hydrogen is attracted to lone pairs on nitrogen, oxygen, or fluorine. These molecules are highly electronegative and form strong bonds with hydrogen
What are Ion-dipole forces?
These atrractions occur between an ion (charged molecule/atom) and a molecule with a dipole.
The stronger intermolecular forces a compound has, the _________ it’s melting/ boiling point.
Higher
When counting valence electrons a bond counts as how many electrons?
2
Bond formation is considered a energy-________ reaction?
releasing (exothermic)
Which molecules have exceptions to the octet rule, in which they can contain less?
hydrogen, Helium, and lithium = 2 electrons
Beryllium = 4 electrons
Boron = 6 electrons
Which molecules have exceptions to the octet rule, in which they can contain more?
Atoms in the 3rd period and below.
Odd-electron molecules
Typically metals (group 1 & 2) form _____ bonds with nonmetals (especially halogens). The electronegativity for this bind is?
Ionic bonds, electronegativity >1.7
_________ compounds have a crystal lattice structure and high melting points due to the intramolecular forces.
Ionic
__________ dissociates in an aqueous solution, which causes the solution the ability to conduct electricity.
Ionic compounds (electrolytes)
Compared to ionic bonds, the elctronegativity difference for covalent bonds are
Smaller (.5)
______ results from the complete donation or acceptance of electrons from an atom. While ______ share electrons.
Ionic bonds
Covalent bonds
What are the most common polar and nonpolar covalent bonds?
C-H = nonpolar C-N = slightly polar N-H = moderatly polar O-H & F-H = Highly polar C- O = meaningful polar (less than H-O)
What is a coordinate covalent bond?
a bond that forms when a set of lone pair electrons is shared with another atom without electrons to share.
What is bond order?
number of bonds between two atoms
Distinguish between sigma and pi bonds
Sigma bonds are the first single bonds to form (it represents the electrons shared between two molecules).
Pi bonds are each additional bonds
Describe bond length
Distance between bonded atoms, or the distance between the nuclei of the atoms that are in the bond.
Bond length is inversely related to bond order.
single bond = furthest
Describe bond energy
the energy required to break covalent bonds.
The higher the bond energy (triple) the harder to break. Bond energy is therefore directly related to bond order.
What is formal charge?
The disparity between the number of valance electrons an atom should have (periodic table) and the number it actually has.
What is the equation for formal charge?
FC = Valence elctrons - 1/2bonding electrons - Lone pairs of electrons
Discuss hybridizations of orbitals
1s 1p = 2 sp orbitals 1s 2p = 3 sp2 orbitals 1s 3p = 4 sp3 orbitals Determine electron density around atom (bonds or lone pairs). If there are two region = sp three regions = sp2 four regions = sp3
What is the VESPR theory?
uses # of bonds and lone pairs to predict shape
What are the various angles of VESPR?
Bent (water) - 104.5 Trigonal pyramidal - 107 Tetrahedral - 109.5 Trigonal planar - 120 Linear - 180
There are a few elements that do not follow the octet rule, what are they?
Hydrogen - only 1
Helium and lithium - maximum of two
Berilium - maximum of 4
Boron - max of 6
When drawing a Lewis dot structure, which atom should be center?
The one with the lowest electronegativity
After forming single bonds and calculating the remaining valence electrons for a Lewis dot structure, where should the remaining electrons go?
To the peripheral atoms
Resonance structures differ in what why?
The distibution of electrons across the molecule
pi electrons should be shifted to different atoms
Given a polyatomic transition metal, such as V(CO3)2, how do you balance?
Determine the charge on the polyatomic ion first (CO3) = CO3, 2-
Since there are 2 of these molecules, it brings the total charge to -4.
Than V must have the oxidation state of 4 (+4).
Vanadium (IV) carbonate
