Bonding and Chemical Interactions

Question 1

Molecules

Answer 1

combining of elements

Question 2

chemical bonds

Answer 2

the strong attractive force that holds most molecules together, formed via the interaction of valence electrons

Question 3

Intermolecular forces

Answer 3

a type of bond that holds molecules together but seen in covalent bonds

Question 4

Octet rule

Answer 4

states that an atom tends to bond with other atoms until it has eight electrons in the outer most shell.

Question 5

Exceptions to the octet rule

Answer 5

Hydrogen (only wants 2)
Lithium (wants 2) and Beryllium (wants 4),
Boron (6) and elements beyond the second row like P and S which can use their d orbitals

Question 6

Ionic bonding

Answer 6

an electrons from an atom with a smaller ionization energy is transferred to an atom with greater electron affinity. (non metal and metal)

Question 7

Covalent bonding

Answer 7

and electron pair is shared between two atoms (non metal to nonmetal)

Question 8

partially covalent and partially ionic are called

Answer 8

polar covalent bonds

Question 9

cation

Answer 9

atom that looses electrons and becomes positively charged

Question 10

anion

Answer 10

atom that gains electrons and becomes negatively charged

Question 11

Ionic bond characteristics

Answer 11

high melting and boiling points, can conduct electricity in aqueous states not solid. very strong electrovalent bond

Question 12

covalent bond characteristics

Answer 12

the binding force is weak intermolecular forces. consequently they have low melting points and do not conduct electricity

Question 13

properties of covalent bonds

Answer 13

two atoms sharing one electron is single covalent bond, two is double and three is triple. They also have bond orders of one two and three.

Question 14

a covalent bond can be characterized by what two features

Answer 14

bond length and bond energy

Question 15

bond length

Answer 15

the average distance between the two nuclei of the atoms involved in the bond. As the number of electrons shared increases the bond shortens. triple bond is shorter than dbl and dbl is shorter than single.

Question 16

bond energy

Answer 16

the energy required to separate two bonded atoms. The strength of the bond (and bond energy) increases as the number of shared electrons increases

Question 17

lone electron pairs

Answer 17

unshared electron pairs

Question 18

Lewis structure

Answer 18

used to represent the bonding and non-bonding electrons in a molecule. The chemical symbol of an element surrounded by dots representing the s and p valence electrons of the atom.

Question 19

1st step in making Lewis Structure

Answer 19

write the skeletal structure of the compound, with the least electronegative atom in the center. H is always at the end.

Question 20

2nd step is making Lewis structure

Answer 20

Count all the valance electrons of the atoms in the compound. then create a single bond (electron pair) between the central atom and the surrounding atoms.

Question 21

3rd step in making Lewis structure

Answer 21

complete the octet for all atoms surrounding the central atom. place any extra electrons on the central atom. if the central atom has less than 8 then make double or triple bonds with the non bonding electron pairs.

Question 22

formal charges

Answer 22

when there is a difference of electrons officially assigned to an atoms in a Lewis structure is different from its actual valence.
formal charge= V(valence)– (1/2)N bonding–N nonbonding

Question 23

Resonance

Answer 23

when two or more non identical Lewis structures can be made for the same compound.

Question 24

resonance determining rules

Answer 24

most stable wins:
the structure with small to no formal charges is preferred
the structure with the formal charge on the most electronegative is more stable

Question 25

Polar covalent bond

Answer 25

occurs between atoms with small differences of electronegative. an unequal sharing of electrons. being pulled more by the electronegative atoms.

Question 26

non polar covalent bond

Answer 26

between atoms that have the same electrognegativites. the electron bonding is shared equally. Occurs is diatomic molecules such as H, Cl, O and N

Question 27

Coordinate covalent bond

Answer 27

the shared electron pair comes from the lone pair of one of the atoms in the molecule. typically found in Lewis acid-base compounds.

Question 28

Lewis acid

Answer 28

a compound that can accept an electron pair to form a covalent bond.

Question 29

Lewis base

Answer 29

a compound that can donate and electron to form a covalent bond

Question 30

VSEPR

Answer 30

valence shell electron-pair repulsion theory.
3D arrangement of atoms surrounding a central atom is determined by repulsions the bonding and non bonding electron pairs.

Question 31

electron repulsions

Answer 31

electron pairs arrange themselves as far apart as possible , thereby minimizing repulsion

Question 32

Steps to predict the geometrical structure of a molecule using VSEPR

Answer 32

1. draw Lewis structure of molecule
2. count the total number of bonding and nonbonding electrons around the central atom (double and triple bonds act as single)
3. arrange the electron pairs so they are as far apart as possible.

Question 33

Geometry for Electron density of 2

Answer 33

liner 180 degrees

Question 34

Geometry for Electron density of 3

Answer 34

trigonal planar 120 degrees

Question 35

Geometry for Electron density of 4

Answer 35

tetrahedral 109.5 degrees

Question 36

Geometry for Electron density of 5

Answer 36

trigonal bipyrimidal 90,120,180 degrees

Question 37

Geometry for Electron density of 6

Answer 37

octahedral 90,180 degrees

Question 38

Polar vs Non polar

Answer 38

a molecule that is non polar will always be non polar. but a polar molecule that has a net zero dipole moment can be non polar as well. due to the cancellation of dipoles.

Question 39

sigma

Answer 39

orbitals overlap head to head resulting in a sigma bond

Question 40

pi

Answer 40

when the orbitals are parallel overlapping p orbitals bond is formed

Question 41

intermolecular forces

Answer 41

hydrogen bonding, dipole-dipole, and dispersion forces or van der waals forces.

Question 42

Dipole dipole interactions

Answer 42

when polar molecules orient themselves in such a way the that the more positive region of one molecule is close to the negative region of another molecule. present in only solids and liquids

Question 43

hydrogen bonding

Answer 43

when the hydrogen in bonded to highly electronegative elements such as O, F, N. highest mp and bp

Question 44

Dispersion forces

Answer 44

London forces, weaker than other intermolecular forces, seen in larger molecules