Chapter 7 - Periodicty

Question 1

The periodic is divided into blocks. What are the four block and what elements do they contain?

Answer 1

• s-block = group 1/2
• d-block = group 3/4/5/6/7/8/9/10/11/12
• p-block = 13/14/15/16/16/18
• f-block = the lanthanides and actinides

Question 2

Complete the sentence:
•the elements are arranged in vertical columns called …………
•the earnest are arranged in horizontal columns called ……

Answer 2

• groups

* periods

Question 3

What Is periodicity?

Answer 3

A repeating trend in properties of the elements across each period of the periodic table

Question 4

What properties are included in periodicity?

Answer 4

• electron configuration
• ionisation energy
• structure
• melting points

Question 5

What is ionisation energy?

Answer 5

Is the energy required to remove 1 electron from a mole of gaseous atom ions

Question 6

Complete the first ionisation energy:

X(g) -> ………

Answer 6

X(g) -> X^+ (g) + e^-

Question 7

Factors effecting ionisation energy:
•
•
•

Answer 7

• atomic radius - the greater the distance between the nucleus and outer electrons the less nuclear attraction
• Nuclear charge - more protons in nucleus of atom the greater the attraction
• electron shielding - electrons negatively charmed and so inner-shell electrons repel outer-shell. The increase in shielding reduces the attraction.

Question 8

What are the trends in first ionisation energy down a group?

Answer 8

• atomic radius increases
• more inner shells so shielding increases
• nuclear attraction on outer electrons decrease
• first ionisation energy decreases

Question 9

What are the trends in first ionisation across a period?

Answer 9

• nuclear charge increase
• same shell : similar shielding
• nuclear attraction increases
• atomic radius decreases
• first ionisation energy increases

Question 10

What is second ionisation energy?

Answer 10

The energy required to remove one electron from each atom in one mole of gaseous 1+ ions of an element to form one mole of gaseous 2+ ions

Question 11

Describe the general trend of the graph showing the ionisation number

Answer 11

There is a general increase until a change from n = 2 shell to n = 1 shell, which steeply increase in first ionisation energy due to being much closer to the nucleus

Question 12

What three factor need to be taken into consideration when making a prediction of the successive ionisation?

Answer 12

• the number of electrons in the outer shell
• the group of the elements in the periodic table
• the identity of an element

Question 13

On a graph which group of element always peek when in first ionisation in their period?

Answer 13

The noble gases

Question 14

What is a metallic bond?

Answer 14

Is a strong electrostatic attraction between cation and delocalised electrons.
Metal + metal

Question 15

Are all metals solid at room temperature?

Answer 15

Yes, except for mercury

Question 16

Describe the metallic structure

Answer 16

• each atom donate negative outer shell electrons to be shared with delocalised electrons
• known as giant metallic structure

Question 17

Properties of metals:
•
• 
•
•

Answer 17

• strong metallic bond
• high electrical conductivity - delocalised electrons move through structure carrying charge
• high melting and boiling points - depends on strength of the bonds. Most need a high amount of energy to over come electrostatic attraction
• solubility - metals don’t dissolve. More likely to be reaction than the metal dissolving

Question 18

What’s a giant covalent lattice?

Answer 18

A three-dimensional structure of atoms, bonded together by strong covalent bonds.

Question 19

What are the properties of giant covalent structures?

Answer 19

• Melting/boiling point- high due to strong covalent bonds
• solubility - giant covalent lattice it is insoluble in most solvents as the bonds are too strong to be broken in interaction
• Electrical conductivity - non-conductors except for graphene and graphite

Question 20

Describe:
•graphene
•graphite

Answer 20

Graphene
•single layer of graphite
•hexagonally arranged - bond by strong covalent bonds
•thinnest and strongest material
•planar hexagonal later (120°) by electron-pair repulsion
Graphite
•parallel layers of hexagonal bonded by weak London Forces
•only uses three out of the four electrons

Question 21

Describe the periodic trends in melting point.

Answer 21

• sharp decrease in melting point from giant to simple molecular structure
• giant metallic structure - strong metallic bonds between cation and delocalised electrons
• giant covalent structure - strong covalent bonds between atoms
• simple molecular structure - weak London Forces between molecules