Chapter 3- Covalent Substances

Question 1

why do non-metallic atoms tend to share electrons

Answer 1

they have a relatively high number of electrons in their outer shells

Question 2

what are intramolecular bonds

Answer 2

bonds within a molecule

Question 3

what is the octet rule

Answer 3

many atoms become more stable if they get an outer shell of 8 electrons

Question 4

what is covalent bonding

Answer 4

the sharing of electrons between atoms

Question 5

what boiling do non-metallic elements and compounds have

Answer 5

low

Question 6

can non-metallic elements and compounds conduct electricity

Answer 6

No

Question 7

Why dont molecular substances conduct electricity

Answer 7

because they dont contain free moving charged particles

Question 8

are intermolecular bonds strong

Answer 8

no hence why they break

Question 9

are intramolecular bonds strong

Answer 9

yes hence why they hold

Question 10

what is a single covalent bond

Answer 10

when atoms share two electrons. one from each atom.

Question 11

what is the molecular formula

Answer 11

an indicator of the number and types of atoms found in a molecule

Question 12

what are electrons involved in the covalent bond called

Answer 12

a shared pair

Question 13

what are electrons that are not involved in the covalent bond called

Answer 13

lone pairs

Question 14

what is a double covalent bond

Answer 14

two pairs of electrons are shared between atoms

Question 15

what are triple covalent bonds

Answer 15

when 3 electron pairs are shared between 2 atoms

Question 16

what does a diatomic molecule contain

Answer 16

2 atoms

Question 17

what is a polyatomic molecule

Answer 17

molecules made up of 2 or more atoms

Question 18

What is the VSEPR theory

Answer 18

a way of predicting the shapes of small molecules

Question 19

How does the VSEPR theory work

Answer 19

the pairs of electrons present in the valence shell will repel each other and try to get as far away from each other as possible

Question 20

Do lone pairs influence the shape of a molecule

Answer 20

Yes but they are not considered a part of the shape

Question 21

What key factor determines the electrons distribution in a diatomic molecule

Answer 21

electronegativity

Question 22

what makes a bond non-polar

Answer 22

if the bond have an equal distribution of electronegativities as there is no charge on either end of the bond

Question 23

what atom has the stronger pull in a covalent bond of 2 different elements

Answer 23

the atom that is the most electronegative

Question 24

in a molecule, which element has a partial negative charge

Answer 24

the element with the higher electronegativity

Question 25

in a molecule, which element has a partial positive charge

Answer 25

the element with the lower electronegativity

Question 26

what is a permanent dipole

Answer 26

the separation into 2 regions as they have two oppositely charges poles at each end of the molecule

Question 27

how do you determine if a molecule is polar

Answer 27

if the difference of electronegativities is greater than 0.5 but less than 1.7

Question 28

what is an ionic bond

Answer 28

electrons are transferred to the more electronegative atom, electronegativity difference must be greater than 1.7

Question 29

what does the polarity of molecules with more than 2 atoms depend on

Answer 29

the shape of a molecule and the polarity of its covalent bonds

Question 30

what is a symmetrical molecule

Answer 30

(evenly distributed polar bonds) they are non polar and cancel each other out.

Question 31

what are asymmetrical molecules

Answer 31

(polar bonds) are polar molecules due to a net dipole being created in the molecule

Question 32

what are the 3 types of intermolecular forces

Answer 32

dispersion forces, dipole-dipole attraction and hydrogen bonding

Question 33

when does the strength of a dispersion force increase

Answer 33

as the relative molecular mass increases. Larger molecules = more electrons = more chance of instantaneous dipoles

Question 34

what is a dispersion force

Answer 34

forces that exist between all molecules whether they are polar or non polar

Question 35

what are dispersion forces caused by

Answer 35

temporary dipoles in the molecules that are the result of random movement of electrons surrounding the molecule

Question 36

what is the weakest of all the intermolecular forces

Answer 36

dispersion forces

Question 37

what is the strongest of all the intermolecular forces

Answer 37

hydrogen bonding

Question 38

what is dipole-dipole bonding

Answer 38

the attraction of dipoles to each other (polar bonds when the partial positive ends of one molecule will be attracted to the partial negative ends of another molecule)

Question 39

when does the strength of a dipole-dipole attraction increase

Answer 39

with increased polarity

Question 40

what is hydrogen bonding

Answer 40

occurs between molecules where hydrogen is bonded to nitrogen, fluorine or oxygen. a non-bonding pair of electrons on the N,O or F atoms of neighboring molecules.

Question 41

what are allotropes

Answer 41

different structural arrangements of the same element

Question 42

what are the allotropes of carbon

Answer 42

graphite and diamond

Question 43

what is the structure of diamond

Answer 43

covalent network lattice

Question 44

why is diamond strong

Answer 44

their are no weak intermolecular forces present

Question 45

what are the properties of diamond

Answer 45

high melting point and sublimation point, does not conduct electricity

Question 46

what is the structure of graphite

Answer 46

covalent layer lattice

Question 47

what are amorphous forms of carbon

Answer 47

charcoal and carbon black. both have no consistent structure