3.1.1 Periodicity

Question 1

How are elements arranged in the periodic table?

Answer 1

They are arranged in the order of increasing atomic numbers

Question 2

What is a period on a periodic table?

Answer 2

The horizontal rows in the periodic table

Question 3

What is a group on a periodic table?

Answer 3

The vertical columns

Question 4

What is meant by periodicity?

Answer 4

The repeating trends in chemical and physical properties

Question 5

What change happens across each period?

Answer 5

Elements change from metals to non metals

Question 6

How can electron configuration be written in short?

Answer 6

The noble gas before the element is used to abbreviate

Question 7

Define first ionisation energy

Answer 7

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

Question 8

Write an equation for the first ionisation energy of magnesium

Answer 8

mg -> mg+ + e-

Question 9

What are the factors that affect ionisation energy?

Answer 9

• Atomic radius
• Nuclear charge
• Electron shielding

Question 10

Why does first ionisation energy decrease between group 2 to 3?

Answer 10

Decreases between 2 to 3 because in group 3 the outermost electrons are in p orbitals whereas in group 2 they are in s orbitals, so the electrons are easier to remove

Question 11

Why does first ionisation energy decrease between group 5 to 6?

Answer 11

The decrease between 5 to 6 is due to the group 5 electrons in p orbitals are single electrons and in group 6 the outermost electrons are spin paired, with some repulsion. Therefore the electrons are slightly easier to remove

Question 12

Does first ionisation energy increase or decrease between the end of one period and the start of next? Why?

Answer 12

Decrease

• There is an increase in atomic radius
• Increase in electrons shielding

Question 13

Does first ionisation increase or decrease down a group? Why?

Answer 13

• Decrease
• Shielding increases thus weaker attraction
• Atomic radius increases thus distance between outer electron and nucleus increases therefore a weaker attraction
• Increase in number of protons is outweighed by increase in distance and shielding

Question 14

What are the properties of giant metallic lattices?

Answer 14

• High melting and boiling point
• Good electrical conductors
• Malleability
• Ductility

Question 15

What is a ductile metal?

Answer 15

The metal can be stretched

e.g. made into wires

Question 16

What is a malleable metal?

Answer 16

The metal can be shaped into different forms

Question 17

Describe the structure, forces and bonding in every element across period 2

Answer 17

Li and Be - giant metallic ; strong attraction between positive ions and delocalised electrons ; metallic bonding

B and C - giant covalent ; strong forces between atoms ; covalent

N2, O2, F2, Ne - Simple molecular : weaker intermolecular forces between molecules ; covalent bonding within molecules and intermolecular forces between molecules