Bonding

Question 1

what is ionic bonding?

Answer 1

when ions are held together by electrostatic attraction

Question 2

what is a compound?

Answer 2

when different elements join or bond together

Question 3

how are ions formed?

Answer 3

when one or more electrons are transferred from one atom to another

Question 4

Sulfate formula

Answer 4

SO4 2-

Question 5

Hydroxide formula

Answer 5

OH-

Question 6

Nitrate formula

Answer 6

NO3 -

Question 7

Carbonate formula

Answer 7

CO3 2-

Question 8

Ammonium formula

Answer 8

NH4 +

Question 9

how do charges help you work out the formula of an ionic compound

Answer 9

the overall charge of any compound is 0

Magnesium chloride contains Mg2+ (+2) and CL- (-1)

because a chloride ion has a -1 charge we will need 2 to balance out the +2 charge of a magnesium ion

MgCl2

Question 10

show which groups in the periodic table loose electrons and which gain when becoming an ion

Answer 10

g1 g2 g6 g7 g8

+1 +2 -2 -1 -+0

Question 11

do ionic compounds conduct electricity?

Answer 11

Yes when molten or dissolved as the ions are free to move and carry a charge

No when solid ions are in a fixed position

Question 12

do ionic compounds have high or low melting points?

Answer 12

Very high

giant ionic lattices are held together by strong electrostatic forces which require lots of energy to overcome

Question 13

do ionic compounds dissolve in water?

Answer 13

Yes

water molecules are polar so the charged parts pull ions away from the lattice causing it to dissolve

Question 14

how are atoms held together in a covalent bond?

Answer 14

two atoms share electrons, so they both have full outer shells of electrons

both positive nuclei are electrostatically attracted to the shared electrons

Question 15

describe the structure of carbon in graphite

Answer 15

layers slide over each other because of weak bonds between layers that are easily broken

delocalised electrons carry a charge so it conducts electricity

low density as layers are far apart

very high melting point as has strong covalent bonds

insoluble as has strong covalent bonds

Question 16

describe structure of carbon in diamond

Answer 16

each carbon is covalently bonded to 4 other carbons

very high melting point

extremely hard

vibrations travel through stiff lattice making it a good conductor of heat

insoluble

Question 17

what is a dative covalent bond?

Answer 17

covalent bond where one of the atoms donates the shared pair of electrons

Question 18

what is a lone pair of electrons?

Answer 18

a pair of electrons that are not shared with another atom

also called non-bonding pairs

Question 19

are bonding pairs or lone pairs more repulsive?

Answer 19

lone pair lone pair is the most repulsive

lone pair bonding pair is in the middle

bonding pair bonding pair is the least repulsive

Question 20

list the steps to work out the shape of a molecule

Answer 20

what group is the central atom in

the group number is the amount of electrons in its outer shell

add how many bonds it makes ( e.g bonds to two other atoms)
to the number of electrons
( group number + number of bonds to other atoms)

divide the number of electrons by 2 to get how many pairs of electrons

take away how many bonds are made from the pairs of electrons to work out the number of lone pairs

Question 21

define electronegativity

Answer 21

an atoms ability to attract the electron pair in a covalent bond

Question 22

what is a dipole?

Answer 22

a difference in charge between two atoms caused by a shift in electron density in the bond

Question 23

describe induced dipole-dipole / Van Der Waals

Answer 23

VDW are present in all atoms and molecules

a temporary dipole in one atom causes another temporary dipole in a neighbouring atom

Question 24

describe permanent dipole-dipole

Answer 24

occurs when two atoms in a molecule have different electronegativity

one atom attracts the electrons more becoming negative while the other atom becomes more positive

Question 25

describe hydrogen bonding

Answer 25

strongest intermolecular force only occurs when hydrogen is bonded to nitrogen, oxygen or fluorine

Question 26

describe the structure of a giant metallic lattice

Answer 26

delocalised electrons mean its a positive metal ion positive metal ions are attracted to delocalised electrons forming a closely packed lattice metallic bonding

Question 27

what are the melting points of metals?

Answer 27

high strong electrostatic attraction between positive ions and delocalised electrons good thermal conductor delocalised electrons pas kinetic energy good electrical conductor delocalised electrons carry a current

Question 28

how are particles arranged in a solid?

Answer 28

particles are very close together high density vibrate in a fixed position

Question 29

how are particles arranged in a liquid?

Answer 29

particles move freely and randomly | quite high density

Question 30

how are particles arranged in a gas?

Answer 30

particles have lots of energy and are far apart | move freely with little FoA

Question 31

which particles have more energy solids, liquids or gasses?

Answer 31

gasses | to break forces between particles you need to add energy

Question 32

what type of structure is most likely to have a low melting point?

Answer 32

simple covalent | you only have to overcome intermolecular forces

Question 33

which structures will conduct electricity when liquid?

Answer 33

ionic because ions are free to move | metallic because of delocalised electrons