Periodicity

Question 1

List and explain the 3 main properties of simple molecular structues

AND NAME SOME EXAMPLES!!

Answer 1

1. LOW MP/BP: low number of electrons = weak, induced London Forces
2. NON-CONDUCTIVE: no delocalised electrons = no charge able to be carried
3. SOLUBLE IN WATER: some molecules may be polar due to electronegativity difference = interact with water

I2,Cl2,O2 and so many more likewise

Question 2

What elements can be remembred as having Giant Covelent Structures?

Answer 2

• Cold Simple Betroots

This shows the NON-METAL ELEMENTS that are able to from these structers in their bonding!!!!

Question 3

List and explain the 3 main properties of Giant Covelent structues

AND NAME SOME EXAMPLES!!

Answer 3

1. VERY HIGH MP/BP: many strong covalent bonds = a lot of energy required to break to change state
2. NON-CONDUCTIVE: Due to having no delocalised electrons able to carry electrical charge (exept graphite due to having mobile electrons)
3. NON-SOLUBLE: Due to covalent bonds far too strong to be brockent and surrouned by water molecules

Graphite,Graphene,Diamond,Silicon Dioxide (sand…)

Question 4

Difference between Bonding and Structure

Answer 4

• BONDING = The chemical interactions that holds the particles in space, forming the overll structure
• STRUCTURE = The original physical construction as a result of bonding

Question 5

Name 4 Bonding and 4 Structural types in chemical compounds

Answer 5

1. BONDING: Ionic, Metallic, Pure Covalent, Polar Covalent
2. STRUCTURAL: Giant Covalent, Giant Metallic, Monoatomic and Simple Molecular

Question 6

Describe Metallic Bonding!!!

Answer 6

1. This is when positive metal ions are surrounded by a sea of delocalised electrons
2. Number of delocalised electrons per metal ion depends on the GROUP NUMBER
3. Will form a giant metallic lattice

Group 1 = 1 delocalised electron per meta

Question 7

List and explain 4 main metallic properties

Answer 7

1. HIGH MP/BP: strong electrostatic forces between ions and electrons
2. DUCTILITY/MALLEABLE: sliding metallic layers
3. CONDUCTIVE: many delocalised electrons able to carry charge
4. NON-SOLUBLE: many string electrostatic forces very hard to break when in solution

Question 8

What would the “graph” trend of Group 2 elements look like in Boiling Points??

Answer 8

1. Rapid Increase from Li to C due to these giant metallic lattices having more very strong electrostatic attration forces!
2. Carbon a NON-METAL with HIGH BP?!??!! = due to forming giant covalent structure, with many strong such bonds
3. 2. Sharp decrease from C to Ne due to sudden transition from metals to non metals, now being simple molecular substances = Very weak London Forces

Question 9

What would the “graph” trend of Group 2 elements look like in Boiling Points??

Answer 9

1. Rapid Increase from Na to Si due to these giant metallic lattices having more very strong electrostatic attration forces!
2. Silicon a NON-METAL with HIGH BP?!??!! = due to forming giant covalent structure, with many strong such bonds
3. 2. Sharp decrease from Si to Ar due to sudden transition from metals to non metals, now being simple molecular substances = Very weak London Forces

Question 10

Wht is periodicity?

Answer 10

• This is the repeating trend in the properties of elements across the periods in the Periodic Table

Heavily influenced by electronic configuration

Question 11

Define the 1st Ionisation Energy!

Answer 11

• The enthalpy change when 1 mole of electrons are removed from 1 mole of gaseous atoms to from 1 mole of gaseous ions!

Question 11

How is the modern-day periodic table arranged

Answer 11

• Elements arragned in ATOMIC NUMBER and not anything but…….

Question 12

List and explain the 3 main factors in ionisation energies!

Answer 12

1. NUCLEAR CHARGE: more protons in nucleaus = greater force of electrostatic attraction with outer shell electrons
2. ATOMIC RADIUS: greater distance from the nucleus = weaker e-attraction forces with outer electrons
3. SHEILDING: more inner electrons = more like charges repelling = easier to remove these outer electrons

Question 13

Defining 2nd, 3rd 4th Ionisation energies

Answer 13

• The same definition as normall, but changing “the changes on the IONS FORMED!!! “

Question 14

Describe and Explain the shape of successive ionisation energies

u know to check here always icl………….

Answer 14

1. GRADUAL INCREASE: upon removing an electron, the remaining electrons are pulled in slightly, decreseing atomic radius
2. SUDDEN INCREASE: removing electrons from the closer energy level requires MUCH MORE energy, as well as decrease in shielding

ALWAYS MENTION “ENERGY REQUIRED” ON ENERGIES……!

Question 15

Units for Ionisation Energies!

Answer 15

KJmol1-

Question 16

How can we use successive ionisation energies to predic elements?

Answer 16

1. First massive energy jump = new energy level (n)
2. Number of electrons before this occurs = Group Number
3. Number of massive energy jumps = Period Number

Question 17

Describe and Explain trend in ionisation energies down the group!

Answer 17

1. Decrease in ionisation energies!
2. Increasing shielding effect from increasing shell numbers
3. Increasing atomic radius (due to same reason)
4. WEAKER ELECTROSTATIC FORCES WITH e- MEANS LESS ENERGY TO REMOVE e-

Question 18

Describe and Explain trend in ionisation energies across the period!

Answer 18

1. Increase in ionisation energies!
2. Increasing nuclear charge
3. Slight decrease in atomic radius (due to increased e-force attaction)
4. GREATER ELECTROSTATIC FORCES WITH e- MEANS MORE ENERGY TO REMOVE e-

very clearly portrayed upon an “ionisation energy” graph!!

Question 19

Why is the an anomaly in Nitrogen and Oxygen in ionisation energy?

Answer 19

1. Their electron configuration marks starting point 2p sub-shell electron pairing
2. As e- have like charges, this means that electron-electron repulsion will occur
3. N>O in energies………..

very clearly portrayed upon an “ionisation energy” graph!!

Question 20

Why is the an anomaly in Beryllium and Boron in ionisation energy?

Answer 20

1. Their electron configuration marks starting point 2p sub-shell filling in next energy level!
2. As greater energy levels have lower energies, less energy is required to remove e-
3. Be>B in energies………..

very clearly portrayed upon an “ionisation energy” graph!!

Question 21

why would elements in groups have similar chemical properties??

Answer 21

DUE TO HAVING SIMILAR ELECTRONIC STRUCTURES!