Periodicty

Question 1

How are elements arranged in a periodic table?

Answer 1

In 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 relating 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 electronic 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 (g) —> Mg+ (g) + e-

Question 9

What are the factors that effect ionisation energy?

Answer 9

Atomic radius
Nuclear charge
Electron shielding

Question 10

Explain the trend in ionisation energy across period 3

Answer 10

First ionisation energy increases across period 3 because of:
Increased nuclear charge
Decreased atomic radius
Same electronic shielding
Which means more energy is needed to remove the first electron

Dips at Al because outer electron is in a 3p orbital, higher energy than 3s orbital —> less energy is needed to remove the electron
Dips at S because one 3p orbital contains 2 electrons, so the repulsion between paired electrons as less energy is needed to remove one.

Question 11

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

Answer 11

Decrease between 2 to 3 because in group 3 the outermost electrons are in p orbitals whereas in group 2 they are in s orbital, so the electrons are easier to be removed.

Question 12

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

Answer 12

The decrease between 5 to 6 is due to group 5 electrons in p orbital 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 13

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

Answer 13

Decrease:
There is an increase in atomic radius
Increase in electron shielding

Question 14

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

Answer 14

Decrease:
Shielding increases —> weaker attraction
Atomic radius increases —> distance between the outer electrons and nucleus increases —> weaker attraction.
Increase in number of protons is outweighed by increase in distance and shielding

Question 15

What are the properties of giant metallic lattices?

Answer 15

High melting and boiling point
Good electrical conductors
Malleability
Ductility

Question 16

What is a ductile metal?

Answer 16

The metal can be stretched e.g made into wires

Question 17

What is a malleable metal?

Answer 17

The metal can be shaped into different forms

Question 18

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

Answer 18

Li & Be - giant metallic : strong attraction between cations and delocalised electrons ; metallic bonding

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

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

Question 19

Describe the structure forces and bonding in every element across period 3

Answer 19

Na, Mg, Al, - giant metallic: strong attraction between cations and delocalised electrons ; metallic bonding

Si - giant covalent : strong forces between atoms : covalent

P4 S8 Cl2 Ar —> simple molecular; weak intermolecular forces between molecules ; covalent bonding with molecules and intermolecular forces between molecules.