covalent bonding again (same thing)

Question 1

covalent bonds are formed by non metals or metals

Answer 1

mon metals

Question 2

non metals can share ____ with other ___ ____ atoms to obtain a ___ ______ ____

Answer 2

electrons
non metal
full outer shell

Question 3

covalent bonds between atoms are very ( weak or strong)

Answer 3

strong

Question 4

covalently bonded substances may be ____________ or _____________

Answer 4

simple molecular structures

giant covalent structures

Question 5

shared electrons are called ______ electrons and are found in ____

Answer 5

bonding

pairs

Question 5

electrons on the ____ shell which are not involved in the covalent bonds are called

Answer 5

non bonding electrons

Question 6

whats the difference between ionic and covalent bonds

Answer 6

in covalent bonds the electrons are shared between the atoms, they are not transferred (donated or gained) and no ions are formed.

Question 7

in a covalent bond, is the electrostatic strong or weak between the shared pair of electrons and why

Answer 7

the electrons are negatively charged and the nuclei are positively charged

Question 8

in covalent bonds, are the electrons in a fixed position

Answer 8

no, they are in constant motion

Question 9

what does covalent bonding do to the atom

Answer 9

makes it more stable

Question 10

covalent bonding forms a

Answer 10

molecule

Question 11

a single covalent bond is shown by

Answer 11

drawing a straight line between them

H-H
Cl-Cl

Question 12

what is a single covalent bond

Answer 12

when one pair of electrons is shared

Question 13

what is a double covalent bond

Answer 13

when 2 pairs of electrons are shared

Question 14

example of an atom that has a double covalent bond

Answer 14

oxygen 0₂

Question 15

how is a double covalent bond represented

Answer 15

two straight lines between the atom
0=0

Question 16

What does diatomic mean

Answer 16

it consists of two atoms covalently bonded together

Question 17

do triple bonds exist

if yes give an example

Answer 17

yes

nitrogen

Question 18

how is a triple bond represented

Answer 18

N≡N

Three lines between the atoms

Question 19

what bond is the strongest (double, single or triple)

Answer 19

triple, it would need a lot of energy to break

Question 20

why is nitrogen so unreactive ( think of bonds)

Answer 20

it has a triple bond which would need huge amounts of energy to break so is a very unreactive gas

Question 21

covalent substances tend to have what structures

Answer 21

simple molecular like Cl₂ or H₂O

Question 22

draw a dot and cross for :
Hydrogen
Chlorine
Nitrogen
Oxygen
Hydrogen Chloride
Water
Ammonia
Carbon Dioxide
Methane
Ethane
Ethene

Answer 22

answers on save my exams

Question 23

what are simple molecular compound made of

Answer 23

a few atoms covalently bonded together

Question 24

why are simple molecular compounds usually liquids or gases at room temperature

Answer 24

they have low melting and boiling points and weak electrostatic attractions between the molecules

Question 25

are simple molecular structures solid at room temp

Answer 25

NO

Question 26

as a simple molecular compound increases in size, what happens to its melting and boiling points and why

Answer 26

As the molecules increase in size the intermolecular forces also increase as there are more electrons available

Question 27

what can be said about the conductivity of simple molecular structures

Answer 27

have poor electrical and thermal conductivity

Question 28

are the covalent bonds strong or weak

Answer 28

strong

Question 29

how can we show that if size increases, so does melting and boiling points ( what do we use/ graph)

Answer 29

we can use alkanes on a graph

Question 30

why can simple molecular compounds not conduct electricity

Answer 30

no free or delocalised electrons so cannot carry a charge

Question 31

simple molecular compounds are ( insulators or conductors)

Answer 31

insulators

Question 32

example of a use of simple molecular structure

Answer 32

coating on an electrical wire ( insulator)

Question 33

as the relative molecular mass of a substance increases, what happens to the melting and boiling points

Answer 33

they also increase

Question 34

why do melting and boiling points increase when relative molecular mass does

Answer 34

there are more electrons in the structure, so there are more intermolecular forces of attraction that need to be overcome when a substance changes state So larger amounts of heat energy are needed to overcome these forces, causing the compound to have a higher melting and boiling point

Question 35

Simple molecular structures are ___ conductors of electricity (even when molten) because (2)

Answer 35

poor there are NO free ions or electrons to move or carry a charge - most covalent compounds do not conduct at all in the solid state and so are insulators -

Question 36

giant covalent structures are ___ at room temperature

Answer 36

SOLID

Question 37

GIANT covalent structures have ___ melting and boiling points

Answer 37

high

Question 38

how are the bonds in a giant covalent structure

Answer 38

very strong

Question 39

GIANT covalent structures can also be called

Answer 39

giant lattices

Question 40

All giant covalent structures have high melting points because: (2)

Answer 40

There are strong covalent bonds between atoms These require lots of energy to overcome