F321: Atomic Structure And Ionisation Energies

Question 0

Mass number

Answer 0

Number of protons + number of neutrons

Question 1

Atomic number

Answer 1

Number of protons

Also number electrons in an atom

Question 2

Electron shells

Answer 2

The main shells (principle energy levels) contain sub shells (s,p,d,f) comprising of orbitals

Question 3

Orbital

Answer 3

Region that can hold up to two electrons with OPPOSITE spins (to reduce the effect of repulsion)

Question 4

Shapes of s and p orbitals

Answer 4

S-orbital is spherical, p-orbital is like a figure of 8 (in 3 orientations px, py, pz)

Question 5

Sub shells

Answer 5

S-sub shell has one orbital (max 2e-), p-sub shell has 3 orbitals (max 6e-) and d has 5 orbitals (max 10e-)

Question 6

Max number of e- in each shell

Answer 6

1st- 2 (1s2)
2nd- 8 (2s2, 2p6)
3rd- 18 (3s2, 3p6, 3d10)

Question 7

Order of filling sub shells

Answer 7

1s 2s 2p 3s 3p 4s 3d 4p 5s

Question 8

Periodic table

Answer 8

An arrangement of elements in order of increasing atomic number.

Question 9

Periods

Answer 9

Rows in the periodic table

Show REPEATING trends in physical and chemical properties

Question 10

Periodicity

Answer 10

Repeating pattern of properties across different periods

Question 11

Groups

Answer 11

Columns in the periodic table

Similar properties due to similar outer shell electron arrangements

Question 12

Metals

Answer 12

Generally loose electrons and form positive ions

Question 13

Non-metals

Answer 13

Generally gain electrons and form negative ions

Question 14

First ionisation energy

Answer 14

Energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions

Eg. Cl(g) -> Cl+(g) + e-

Question 15

Second ionisation energy

Answer 15

Energy required to remove one electron from each ion in one mole of gaseous 1+ ions to from one mole of gaseous 2+ ions

Question 16

Successive ionisation energies

Answer 16

Increase because of increased attraction due to the same number of protons attracting fewer electrons. Therefore atomic radii decreases.
A large increase identifies a change in shell due to a decrease in shielding so more energy is needed to remove the electron. This can be used to identify the group an atom is in.

Question 17

Trends in 1st ionisation energies down group

Answer 17

Decreases down group:
Increase in nuclear charge outweighed by more shielding, increase in atomic radii, therefore outer shell electrons experience less attraction and are lost more easily.

Question 18

Trends in 2nd ionisation energies down groups

Answer 18

Same for 1st ionisation energies but use ionic radii rather than atomic radii.

Question 19

Trends in 1st ionisation energies across periods

Answer 19

Increases across period:
Outer shell electrons in the same shell so same shielding, nuclear charge increases due to more protons, hence outer shell electrons are attracted more strongly to the nucleus and are lost less easily.
(Also explains why atomic radii decreases across the period)