Periodic table & periodicity

Question 1

Periodic table arrangment

Periodicity definition

Periodic trend in electron configuration

Answer 1

Arranged in order of increasing atomic number

Periodicity is the repeating trend in properties of elements.

s,p,d,f blocks
Shows what subshell the highest energy electron is in.

Look at kerboodle textbook pg 94 for detail.

Question 2

Ionisation energy
First ionisation energy

Factors affecting ionisation energy

Answer 2

How easily an atom loses an electron to form an ion

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

• Atomic charge- more protons, greater attraction between nucleus and outer electrons
• Atomic radius- smaller distance between nucleus and electrons, greater attraction
• Electron shielding- more electrons, more repulsion (shielding effect), less attraction

Question 3

Successive ionisation energy graph

Answer 3

x axis- ionisation number
y axis- ionisation energy

Ionisation energy increases as ionisation number increases.
Ionisation number starts from outer shell.
Big jumps indicate change of shell (closer to nucleus).

Question 4

Trends in first ionisation energy:
- Down a group
- Across a period

Answer 4

Down a group, atomic radius increases, shileding increases, charge remains the same, so nuclear attraction to outer electrons decreases, so ionisation energy decreases.

Across a period, charge increases, atomic radius decreases, shielding remains the same, so nuclear attraction to outer electrons increases, so first ionisation energy increases.

Question 5

Subshell trends in first ionisation energy

Answer 5

General increase as atomic number increases, however, drop from nitrogen to oxygen, then from berrylium to boron.

Berrylium to boron marks filling of 2p subshell, which has a higher energy, so easier to remove.
Nitrogen to oxygen marks the start of electron pairing in 2p subshell, which increases repulsion between electrons, making them easier to remove.

Question 6

Giant metallic structures (metallic bonding)

Properties

Answer 6

The strong electrostatic attraction between cations and delocalised electrons.
In a metal structure, each atom has donated its valence electrons. Forms a sea of delocalised electrons.

Properties:
-Can conduct electricity- delocalised electrons are not fixed in position and are mobile charge carriers.
- high m.p and b.p- strong electrostatic attraction ebwteen cations and delocalised electrons, strong metallic bonds
-low solubility- do not dissolve in water.

Question 7

Giant Covalent structures

Properties

Answer 7

Carbon and silicon form giant covalent lattice- 109.5, tetrahdral.

• high m.p and b.p- strong covalent bonds
• insoluble- covalent bonds too strong to be broken by interactions with solvents
• Non-conductors of electricity- no free electrons to carry charge.

Apart from graphite and graphene- ony 3 carbons are used in covalent bonding, so each has 1 free electron, forming sea of delocalised electrons.