Atomic Structure

Question 1

Rutherford

Answer 1

Discovered the proton by firing alpha particles through a gold sheet and recording how many passed through or bounced back. Also credited for the first suggestion that the bulk of mass is located in nucleus.

Question 2

Thomson discovered

Answer 2

The electron

Question 3

Chadwick

Answer 3

Discovered the neutron

Question 4

Electron mass

Answer 4

1/1840

Question 5

What is an isotope

Answer 5

Atoms of the same element (same number of protons) but a different number of electrons hence a different mass number

Question 6

Relative Atomic Mass

Answer 6

Weighted mean mass if an atom compared ti 1/12th of carbon 12

Question 7

Relative isotopic mass

Answer 7

Mass if an isotope compared to 1/12th of carbon 12

Question 8

RFM/relative molecular mass

Answer 8

Sum of all relative atomic masses in a compound (not the stoichiometric numbers)

Question 9

mass spectrometer function

Answer 9

Measures the masses of molecule by producing positive ions that are deflected by a magnetic field according to their mass/charge ratio
Remember the peaks also account for different combinations of weight in diatomic molecules ie 35 & 35 = 70 for chlorine

Question 10

For polyatomic / large molecules the last proper peak on the right is the

Answer 10

Mr = relative molecular mass

Question 11

What is the definition of the first ionisation energy?

Answer 11

The energy required to remove an electron from each atom in one mole of gaseous atoms

Question 12

Trends in ionisation energy across a period

Answer 12

The nuclear charge (number of protons increases)
Shielding (number of inner shells) remains constant
Nuclear attraction on outermost electrons increases
Atomic radius decreases

Overall ionisation energy increases

Question 13

Ionisation energy trends down a group

Answer 13

Nuclear charge increases
Shielding increases
Shielding outweighs nuclear charge so nuclear attraction decreases
Atomic radius increases

Overall ionisation energy decreases

Question 14

Nuclear charge is

Answer 14

The positive charge determined by the number of protons

Question 15

Shielding is

Answer 15

Repulsion experienced by the electron by all other present electrons

Question 16

Nuclear attraction is

Answer 16

The stronger the attraction the closer the electrons and the protons become hence the smaller the radi of the atom

Question 17

Order of orbitals shells subshell

Answer 17

She’ll contains subshell which contains orbitals

Question 18

2p3 explain what each signifies

Answer 18

2nd shell
P subshell
3 electrons in orbital

Question 19

An orbital is

Answer 19

A region of space that can hold upto 2 electrons with opposite spins

Question 20

A subshell is

Answer 20

A collection of (s,p,f,d) orbitals

Question 21

A shell is

Answer 21

A collection of subshell

Question 22

S block p block d block f block describe location on periodic table

Answer 22

Metals = s 
D= transition metals 
P= non metals 
F= radioactive table at bottom

Question 23

Shape of a orbital

Answer 23

A sphere represented as a circle

Question 24

Shape of p orbital

Answer 24

Figure of eight represented either vertically or horizontally.

Question 25

Shorthand configuration (electronic)

Answer 25

In square brackets out the Nobel gas that appears before intended element and then write the remaining configuration.

Question 26

How many electrons (max) in each orbital?

Answer 26

S=2
P=6
D=10
F=14

Question 27

Remember to do what with 4s and 3d orbital

Answer 27

Fill 4s in before 3d because the energy of the 4s is less than that of the 3d hence it is easier to lose electrons from there. The orbitals overlap and 4s is closer to nucleus than 3d

Question 28

Exceptions when filling out electronic configuration

Answer 28

Chromium and Copper have only one electron present in 4s and 5 and 10 respectively in 3d

Question 29

Reason for two element exceptions in electronic configuration (chromium and copper)

Answer 29

Due to increased stability of filled/ half filled d subshell

Question 30

Hunds rule

Answer 30

No more than two electrons can occupy an orbital ( ie box diagram there are three boxes for p orbital)

Question 31

Pauli’s exclusion principle

Answer 31

Two electrons occupying the same orbital must have opposite spins (box must have two different direction arrows)

Question 32

Atomic Emission Spectra

Answer 32

Lines correspond energy of each shell - shells are of specific energies

Question 33

Successive ionisation energies

Answer 33

Steady increases then a big jump shows which group it belongs in ie big jumps from IE3 to IE4 then element is in group three

Question 34

Periodicity

Answer 34

Repeating pattern of trends across a period

Question 35

Two exceptions to ionisation trends across periods

Answer 35

Group two to group three: an element in group two for example magnesium loses an electron from the 3s subshell whereas aluminium in group three loses from the 3p subshell which is higher in energy hence less energy is needed to lose an electron in group two than three which is an exception

Group five to group six for example oxygen in group six has a paired set of electrons in 2p which they repel each other, hence it is easier for oxygen to lose an electron then nitrogen in group five, which is again an exception.

Question 36

Difference between covalent radi and Van Der Waals

Answer 36

Covalent is distance between nucleus when bonded hence overlap in the other one atoms are just touching (the only radius that can be determined for Neón and argon because they do not bond with other elements)

Question 37

Atomic radi changes how across period and explain

Answer 37

Decreases
Number of protons in nucleus increases hence the nuclea charge increases hence more attraction between nucleus and outermost electrons hence nuclear attraction is increased which pulls the shells closer.

Question 38

Explain the change in the first ionisation energy from hydrogen to helium

Answer 38

Increase in nuclear charge from +1 to +2 so increase in electron - electron repulsion in 1s orbital.