Chemical Bonding

Question 1

What is Electron Negativity?

Answer 1

The ability to attract a shared pair of electrons

Question 2

What is a covalent bond?

Answer 2

2 attoms share a pair of electrons equally

Question 3

What is a polar covalent bond?

Answer 3

when one side of a covalently bonded atom has a greater electron negativity pulling the electrons closer to it making it slightly negative

Question 4

can you get a polar bond but not a polar atom?

Answer 4

yes, polar bonds can cancel each other out.

Question 5

what is the Pouling scale?

Answer 5

it is a scale that assigns each element a value of electron negativity

Question 6

what factors effect EN (electron negativity)

Answer 6

nuclear charge
atomic structure
shielding

Question 7

what difference in EN (electron negativity) makes a pure covalent bond?

Answer 7

less than 1.0

Question 8

what difference in EN (electron negativity) makes a polar covalent bond?

Answer 8

between 1.0 and 2.0

Question 9

what difference in EN (electron negativity) makes a ionic bond?

Answer 9

more than 2.0

Question 10

what is a polar molocule

Answer 10

when one atom in a covalently bonded molecule has a larger EN the electrons are pulled slightly towards it creating different polls on either side of the molecule

Question 11

true or falce. Polar bonds always make polar molocules

Answer 11

Falce. some polar bonds cancel each other

Question 12

what do you call a shell that has more than 8 electrons

Answer 12

electron ritch or expanding the octet

Question 13

what do you call a shell that has less than 8 electrons?

Answer 13

electron-deficient

Question 14

what is a ionic bond formed by?

Answer 14

a meatal and a non-meatal

Question 15

what is a co-ordinate bond or a dative covalant bond?

Answer 15

it is a covalent bond where the shared pair of electrons come from the same atom (must have a lone pair to happen)

Question 16

what is metallic bonding?

Answer 16

it is when meatals are held together by electrostatic forces

Question 17

true or false. at high temperatures aluminium chloride can be a monomer

Answer 17

True

Question 18

what is a dimer?

Answer 18

two molecules bonded together

Question 19

what is hybridisation?

Answer 19

when two shells combine to form a complete orbital

Question 20

what is the dipole moment?

Answer 20

a measure of how polar a molecule is

Question 21

explain an S - S bond

Answer 21

when two S orbitals bond it is called a sigma bond, they bond head on and they combine orbitals with one electron to form a full orbital

Question 22

explain a P - P bond

Answer 22

when two P orbital bond together side on we call this a pi bond they overlap at two points to share electrons thus making them stronger than sigma bonds

Question 23

true or false. pi bonds are stronger than sigma bonds

Answer 23

True

Question 24

define bond energy

Answer 24

the energy required to break one mole of a particular covalent in the gaseous state (measured in kilojoule per mol)

Question 25

define bond length

Answer 25

the internuclear distance between the nucleus of two atoms (shorter bond is strongest e.g triple bond is the shortest and strongest)

Question 26

what is a picometer

Answer 26

1x10^-12 of a meter and used to measure bond length

Question 27

what factors affect the reactivity of covalent bonds?

Answer 27

polarity of bond strength of bond type of bond (sigma or pi)

Question 29

what are diatomic molocules?

Answer 29

F2 Cl2 I2

Question 30

what group are the halogens?

Answer 30

group 17

Question 31

which group has the highest electron negativity?

Answer 31

the halogens (they make the most polar bonds)

Question 32

what is VSEPR theory

Answer 32

valence shell electron pair repulsion (can predict the molecular shape and bond angles of molecules)

Question 33

give the order of repulsion in VSEPR theory

Answer 33

(lone pair - lone pair) > (lone pair-bond pair) > (bond pair - bond pair)

Question 34

what is the agle of a linear molecule?

Answer 34

180 degrees

Question 35

what is the angle between bonds of a trigonal plainer?

Answer 35

120 degrees

Question 36

what is the angle between bonds of a Trigonal Pyramidal?

Answer 36

107 degrees

Question 37

what is the angle between bonds of a Tetrahedral?

Answer 37

109.5 degrees

Question 38

what is the angle between bonds of a trigonal bipyramidal

Answer 38

120 and 90 degrees

Question 39

what is the angle between bonds on a octahedral?

Answer 39

90 degrees

Question 40

intramolecular bond

Answer 40

a bond within a molecule (i.e between two atoms)

Question 41

intermolecular force (IMF)

Answer 41

forces (sometimes bonds) between molecules.

Question 42

what bonds have the highest IMF (intramolecular force)

Answer 42

hydrogen bonds (pd - pd bond)

Question 43

define a dipole

Answer 43

a molecule that has a slight charge difference across it

Question 44

define a species

Answer 44

atom or molocule

Question 45

what is needed for hydrogen bond?

Answer 45

1. a species with an O or N with an available lone Pair 2. a species with an -OH or -NH group

Question 46

what does the number of hydrogen bonds in one atom depend on?

Answer 46

the number of lone pairs (i.e no molecule can have more than two hydrogen bonds)

Question 47

what properties does hydrogen give whater?

Answer 47

High melting and boiling points High surface tension anomalous densitys of ice compared to water

Question 48

what is the enthalpy of vaporisation?

Answer 48

the energy required to boil a substance

Question 49

define a hidride

Answer 49

anything that contains a hydrogen

Question 50

define an instantanius dipole

Answer 50

a type of IMF that is temporary (id - id forces)

Question 51

in what molecules do instantaneous dipoles occur?

Answer 51

all molecules but especially in non-polar molecules (chances increase with the number of electrons)

Question 52

define surface tention

Answer 52

the ability of a liquid surface to resist any external forces (I.e the stay unaffected by forces action on the surface)

Question 53

why is surface tention a thing

Answer 53

because intermolecular forces between the surface and lower molecules pull the surface molecules down towards the water and to each other above it

Question 54

what is a dipole moment?

Answer 54

a measure of how polar a molecule is

Question 55

how do you show which is the negative end of polar molecule?

Answer 55

point an arrow towards the negative end of the molocule

Question 56

what are van der waals forces?

Answer 56

they are intermolecular forces between molecules

Question 57

what are id - id (instantanius dipole) forces also know as?

Answer 57

London dispersion forces

Question 58

what are London dispersion forces caused by?

Answer 58

a shift in the electron cloud in a molecule

Question 59

when will london dispersion forces increce?

Answer 59

increces with elecron and atomic number but also in places where molocules come close together

Question 60

what are the strongest to weakest bonds

Answer 60

Covalent bond ionic bond Metalic bond hydrogen bond pd - pd forces id - id forces