1. Atomic Structure and The Periodic table

Question 1

Definition of relative atomic mass

Answer 1

weighted mean mass of an atom of an element compared to 1/12th of the mass of a carbon-12 atom

Question 2

definition of relative isotopic mass

Answer 2

the mass of an atom of an isotope compared to 1/12th of the mass of a carbon-12 atom

Question 3

definition of relative molecular/formula mass

Answer 3

average mass of a molecule compared to 1/12th of the mas of a carbon-12 atom

Question 4

how do you work out relative molecular mass?

Answer 4

add up the atomic mass values of all atoms in the molecule

Question 5

how do you work out relative formula mass

Answer 5

add up atomic mass for all ions and atoms

Question 6

how do you work out relative atomic mass from isotopic abundances

Answer 6

1. multiple relative isotopic mass by its abundance and add the results together
2. divide by 100

Question 7

what does mass spectrometry show

Answer 7

what samples are made from by looking at their masses

Question 8

how do you work out the relative atomic mass of different elements

Answer 8

1. ,multiple each relative isotopic mass by their abundance and then add together
2. divide by the sum of isotopic abundances

Question 9

how to calculate relative isotopic masses from relative isotopic mass

Answer 9

find the abundance of the missing isotope and substitute into the equation and solve

Question 10

how to predict the mass spectra for diatomic molecules

Answer 10

1. express each percentage as a decimal
2. make a table of all possible diatomic molecules
3. multiply decimal abundances together
4. any molecules with the same product add together
5. divide all abundances by the smallest relative abundance getting the smallest whole number ratio

Question 11

what is an orbital

Answer 11

regions of space where electrons are most likely to be found

Question 12

subshell notation

Answer 12

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6

Question 13

configuration of chromium and copper

Answer 13

they donate one of their 4s electrons to 3d subshell because its more stable with a full or half full d subshell

Question 14

first ionisation energy

Answer 14

energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions

Question 15

second ionisation energy

Answer 15

energy needed to remove 1 electron from each ion in 1 mole of gaseous 1+ ions to form one mole of gaseous 2+ ions

Question 16

what is periodicity

Answer 16

all elements have the same number of electron shells so there are repeating trends in physical and chemical properties

Question 17

what decides chemical properties

Answer 17

electron configuration

Question 18

what happens to atomic radius across a period

Answer 18

it decreases as the postive charge of the nucleus pulls the outer electrons closer

Question 19

3 factors that affect ionisation energy and how do they affect it

Answer 19

nuclear charge : more protons = more positive = stronger attraction

electron shell : attraction falls with distance. more shells = less attraction

shielding : number of electrons increases = attraction decreases

Question 20

what happens to ionisation energy across a period

Answer 20

it increases due to stronger nuclear attraction

Question 21

why does ionisation energy drop between group 2 and 3

Answer 21

group 3 outer electron is in 3p orbital which has a higher energy to it is further from the nucleus and easier to remove

Question 22

why does ionisation energy drop between group 5 and 6

Answer 22

in phosphorus the electron is removed from a singly occupied orbital. in sulphur it is removed from a pair so it is easier to remove due to repulsion.

Question 23

metals melting and boiling points across a period

Answer 23

increases as number of delocalised electrons increases which decreases the radius

Question 24

giant covalent structure melting and boiling points

Answer 24

strongest due to covalent bonds between all the atoms

Question 25

simple molecular structure melting and boiling points

Answer 25

low due to weak london forces

Question 26

noble gas melting and boiling points

Answer 26

lowest melting and boiling points as individual atoms (monatomic) have weak london forces

Question 27

what does isoelectronic mean

Answer 27

have the same number of electrons or same electronic configuration

Question 28

what is electromagnetic radiation

Answer 28

the energy transmitted as waves with a spectrum of different frequencies

Question 29

what do emission spectrums show

Answer 29

frequencies of light when electrons drop to lower levels. these appear as coloured lines on a dark background

Question 30

4 basic principles of the idea of quantum shells

Answer 30

1. electrons can only exist in fixed orbitals
2. each shell has a fixed energy
3. when an electron moves between shells electromagnetic radiation is emitted or absorbed
4. because the energy of shells is fixed the radiation will have a fixed frequency