Bonding, structure and electrons

Question 1

what are the sub shells ?

Answer 1

s - p - d - f

Question 2

what is spin pairing ?

Answer 2

two electrons in an orbital with opposite ‘spins’

Question 3

what shape are s orbitals ?

Answer 3

spherical

Question 4

what shape are p orbitals ?

Answer 4

dumbbell shaped

Question 5

what to remember with electron configuration ?

Answer 5

4s sub shell has lower energy level than 3d sub shell (so fills first in graph)

Question 6

why can ionic compounds conduct when molten ?

Answer 6

ions are mobile and able to carry charge

Question 7

why do ionic compounds have high melting points ?

Answer 7

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

Question 8

why do ionic compounds tend to dissolve in water ?

Answer 8

polar water molecules attract to the charged ions and pull them away from lattice

Question 9

whats special about boron trifluoride ?

Answer 9

boron has 6 electrons in its shell

Question 10

whats special about sulfur hexafluoride ?

Answer 10

sulfur has 12 electrons in its shell

Question 11

what is dative covalent bonding ?

Answer 11

when both electrons in a bond come from the same atom

Question 12

what to remember with VSEPR theory ?

Answer 12

lone pair of electrons repel more than bonding pair

Question 13

define electronegativity

Answer 13

an atom’s ability to attract the electron pair in a covalent bond

Question 14

what are the most electronegative elements ?

Answer 14

fluorine — oxygen, nitrogen, chlorine

Question 15

what is electronegativity measured on ?

Answer 15

Pauling scale

Question 16

what makes a bond polar ?

Answer 16

bonding electrons pulled closer towards more electronegative atom

Question 17

what does the difference in electronegativity between two atoms create ?

Answer 17

permanent dipole

Question 18

what determines whether the molecule will have an overall dipole (is polar) ?

Answer 18

the arrangement of the polar bonds

Question 19

if the polar bonds are symmetrical …

Answer 19

dipoles cancel, so no overall dipole so non-polar

Question 20

if the polar bonds are non-symmetrical …

Answer 20

charge is arranged unevenly, so there is an overall dipole, so is polar

Question 21

what are the 3 intermolecular forces ?

Answer 21

London forces / permanent dipole - dipole interactions / hydrogen bonding

Question 22

what are the other names for London forces ?

Answer 22

Van der Waals / induced dipole-dipole

Question 23

where are London forces present in ?

Answer 23

between all atoms / molecules

Question 24

simply describe what London forces are

Answer 24

electrons always moving in atom, one side will have

more, creates temporary dipole (which induces dipole on other atoms) - always changing

Question 25

what increases strength of London forces ?

Answer 25

• larger no. of electrons

- greater contact area

Question 26

what are permanent dipole-dipole forces ?

Answer 26

weak electrostatic forces of attraction between molecules caused by delta charges on polar molecules

Question 27

hydrogen bonds can only form when …

Answer 27

covalently bonded to fluorine / nitrogen / oxygen

Question 28

what is a hydrogen bond ?

Answer 28

weak bond between hydrogen and lone pair of electrons from N, F, O due to the bond being so polarized

Question 29

why is ice less dense than water ?

Answer 29

water molecules held in a lattice and have more hydrogen bonds in ice

Question 30

why do simple covalent compounds have low melting / boiling ?

Answer 30

weak intermolecular forces holding together molecules don’t require much energy to break

Question 31

why are polar molecules soluble in water ?

Answer 31

hydrogen bonds form with water molecules, making it soluble

Question 32

why don’t simple covalent compounds conduct electricity ?

Answer 32

no charged particles to carry the charge

Question 33

what must you do to melt / boil and simple covalent compound ?

Answer 33

overcome intermolecular forces (not strong covalent bond)