The Periodic Table and energy

Question 1

What are groups in the periodic table?

Answer 1

They are vertical columns that have elements with the same number of electrons in their outer shell and so they have similar chemical properties.

Question 2

What are periods in the periodic table?

Answer 2

They are horizontal rows that have elements with the same number of highest energy electron shell

Question 3

How are the elements arranged in the periodic table?

Answer 3

The elements are arranged in order of increasing PROTON number

Question 4

What is Periodicity?

Answer 4

It is a pattern of repeating trends across periods

Question 5

What is the periodic trends for electron configuration across periods?

Answer 5

Across periods, each successive elements gains one electron

Question 6

What is the periodic trends for electron configuration down a group?

Answer 6

Down a group, the number of electrons in each outermost shell and type of sub shell stays the same

Question 7

What is Ionisation energy?

Answer 7

it is the energy needed to remove electrons

Question 8

What is the first ionisation energy?

Answer 8

It is the energy needed to remove 1 mole of electrons from 1 mole of gaseous atom to form one mole of gaseous 1+ ions

Question 9

Factors affecting IE

Answer 9

Atomic radius
Nuclear charge
Electron shielding

Question 10

How does Atomic radius affect IE

Answer 10

The greater the atomic radius between the nucleus and outer electron shells, the weaker the nuclear attraction and so the smaller than IE

Question 11

How does Nuclear charge affect IE?

Answer 11

The more positively charged the nucleus is, the stronger the attraction between the nucleus and the outer electron shells and so the greater the IE

Question 12

How does Electron Shielding affect IE?

Answer 12

The greater the number of inner shells, the greater the shielding from the nucleus to the outer electron shell therefore the weaker the nuclear attraction which reduces the IE

Question 13

Trends in IE down a group.

Answer 13

Down a group, the IE decreases. This is because the atomic radius increases because there are more inner shells so shielding increases. This increased shielding decreases the nuclear attraction between the nucleus and the outer electron so less energy is needed to remove them, so IE decreases.

Question 14

Trends in IE across a period

Answer 14

Across a period, the IE increases. This is because nuclear charge increases, which increases the nuclear attraction between the nucleus and outer electron shell, decreasing the atomic radius. This requires more energy to remove the outer electron so IE increases

Question 15

Exceptions to increasing IE across period 2 and 3- Be to B

Answer 15

In Boron, the outer electron is in a p-sub-shell which is of a higher energy than a s-sub-shell and also further away from the nucleus. Because of this, the 2p electron in Boron is easier to remove than the 2s electron so it has a lower IE than beryllium

Question 16

Exceptions to increasing IE across period 2 and 3- N to O

Answer 16

Oxygen has a lower IE than Nitrogen because one of oxygen 2p orbitals has a pair of electrons which repel each other making it easier to remove an electron.

Question 17

What does this provide evidence for?

Answer 17

It provides evidence for the existence of sub-shells, their energies and how orbitals fill with electrons

Question 18

What predictions can be made from successive IE values?

Answer 18

1. The number of electrons in their outer electron shell which equals the group number
2. the identity of the element