bonding

Question 1

ionic bonding

Answer 1

the electrostatic force between oppositely charged ions formed by electron transfer

Question 2

what charges to metals and non metal form when the ionicly bond

Answer 2

metals lose electrons to form positive ions and non metals gain electrons to form negative ions

Question 3

what is the structure of ionic crystals

Answer 3

giant ionic lattices

Question 4

what causes one ionic bond to be stronger and have a higher melting point compared to another

Answer 4

the ionic bonds are stronger and the melting point higher when the ions are smaller and/ or have a higher charges due to the fact they have greater electrostatic attraction between the ions as they are closer together and/ or higher charges means greater force of attraction

Question 5

why are positive ions smaller in an ionic lattice

Answer 5

positive ions are smaller as they have lost electrons and their outer shell of electrons to get a full outer shell.
they also have more proton then electrons so the ratio has increased and so there is a greater net force on the remaining electrons holding them more closely

Question 6

why are the negative ions in an ionic lattice large

Answer 6

they have not lost any shells and have also gained electrons but not protons so the pull of the nucleus is shared over more electrons making it weaker

Question 7

what happens to the size of the ionic radii as you go down a group

Answer 7

gets larger as more shells of electrons

Question 8

what happens to the size of the nucelli radii as you go across a period

Answer 8

it get slightly smaller as you go across the period due to he fact that as you go across a period the number of protons increases so increased nuclear attraction but they have the same number of shells so the same distance between the outer electrons and protons and a greater force so smaller atom

Question 9

what is a covalent bond

Answer 9

a covalent bond is shared pair of electrons

Question 10

what is a dative covalent bond

Answer 10

a dative covalent bond forms when the shared pair of electrons only come from one of the atoms. (can also be called a co-ordinate bond)

Question 11

common examples of dative bonds (3)

Answer 11

NH4+ H3O+ NH3BF3

Question 12

how do you draw a dative bond on a line drawing

Answer 12

it is an arrow goes from the atom providing the loan pair to the deficient atom

Question 13

definition of metallic bonding

Answer 13

metallic bonding is the electrostatic force of attraction between the positive metal ions and the negative delocalised electrons

Question 14

what are the three main factors that effect the strength of a metallic bond

Answer 14

1- the more protons the stronger the nuclear attraction
2-the more delocalised electrons the stronger the bond
3-the smaller the ion the stronger the bond

Question 15

what structure do ionic bonding form

Answer 15

giant ionic lattice

Question 16

what form to metallic bonds make

Answer 16

giant metallic lattice

Question 16

what are the two types of structures covalent bonds can make

Answer 16

simple molecular and macromolecular

Question 17

properties of ionic lattices

Answer 17

high melting and boiling point- electrostatic attraction lot of energy
soluble
only conductive molten- ions can move
crystalline solids

Question 17

properties of giant covalent structures

Answer 17

high boiling and melting point - strong covalent bonds
insoluble
only graphite can conduct electricity
solids

Question 17

how to calculate the number of loan pairs in a atom

Answer 17

group number fo the central atom - number of atoms bonded all divided by 2

Question 17

properties of simple molecular structures

Answer 17

low melting and boiling points- weak IMF
insoluble
not conductive
mostly gases and liquids

Question 17

why are ionic compounds brittle

Answer 17

when a force is applied it can cause the layers to slide slightly which causes like charges to align up and repel causing to to shatter

Question 17

what is electronegativity

Answer 17

the relative tendency of an atom in a covalent bond in a molecule to attract electrons in a covalent bonds to itself

Question 18

properties of giant metallic lattices

Answer 18

high melting and boiling points- strong electrostatic attraction
insoluble
conductive
shiny malleable metal

Question 18

what is the most electronegative element

Answer 18

Florine

Question 18

what happens to the electronegativity across a period

Answer 18

it increases as the number of protons increase and the atomic radii decreases because electrons in the same shell are puled in more

Question 18

what happens to the electronegativity down a group

Answer 18

it decreases as the distance between the outer electron and the nucleus increases and so the shielding increases

Question 19

how can the difference in electronegativity tell us whether a bond is ionic or covalent

Answer 19

if there is a small difference the bond will be covalent and they will share electrons
if the difference is very substantial the bond will be ionic as one atom will be so much stronger it will pull the electrons completely out of the other atom

Question 20

what does polar mean and when does a polar bond form

Answer 20

polar covalent bond form when there is difference in electronegativity.
when a bond is a a polar covalent bond it has an unequal distribution of electrons in the bond and produce a charge separation (dipole) positive and negative the one with the greater electronegativity will be negative

Question 21

how can you tell is a molecule is polar or non polar

Answer 21

even if their are polar bonds in the molecule a molecule will be non polar is it is symmetrical and has no loan pairs this is because the individual dipoles on the molecule cancel out if it symmetrical so their is no net polar

Question 22

list the three types of intermolecular forces from strongest to weakest

Answer 22

H-H bond
permanent dipole bond
van der Waals bonds (also called transient or temporary dipole dipole bond)

Question 23

where do van der Waal IMF forcers occur

Answer 23

between polar and non polar molecules (not ionic substances)

Question 24

how and why can Van der Waals forces form

Answer 24

since electrons in a molecule are moving consistently and randomly as this happens the electron density can fluctuate creating dipoles
these dipoles can cause dipoles to form in neighbouring molecules these are called induced dipoles and are always the opposite charge of the original one

Question 25

what are the main factors effecting van der Waal bonds

Answer 25

1-number of electrons as more electrons means higher chance of dipoles forming
2-size of the molecule a larger molecule means stronger bonds
3-surface area as a larger or easier surface area mean the molecules can have more points of contact and so more bonds

Question 26

where do permanent dipole dipole bonds form

Answer 26

they form between two polar molecules in addition to van der Waals

Question 27

when do hydrogen bonds form

Answer 27

only between two poler molecules between a positive hydrogen molecule and a loan pair from only one of the most electronegative elements: nitrogen oxygen and fluorine
in addition to van der Walls

Question 28

what does planar mean

Answer 28

all the bonds in the molecule are in the same direction