Topic 1- Atomic structure and periodic table

Question 1

What is the relative atomic mass?

Answer 1

The weighted mean mass of an atom of an element compared to 1/12 of the mass of an atom of carbon-12

Question 2

What is relative isotopic mass?

Answer 2

The mass of an individual atom of a particular isotope relative to 1/12 of the mass of an atom of carbon-12

Question 3

What is Hund’s rule?

Answer 3

Hund’s rule states that electrons will occupy the orbital singly before pairing takes place

Question 4

What is the Pauli exclusion principle?

Answer 4

The Pauli exclusion principle states that two electrons cannot occupy the same orbital unless they have opposite spins

Question 5

What is the first ionisation energy?

Answer 5

The first ionisation energy of an element is the energy required to remove an electron from each atom in one mole of atoms in the gaseous state

Question 6

What is the second ionisation energy?

Answer 6

The second ionisation energy of an element is the energy required to remove an electron from each singly charged positive ion in one mole of positive ions in the gaseous state

Question 7

What are factors that affect the energy an electron has?

Answer 7

• the orbital in which the electron exists
• the nuclear charge of an atom
• the repulsion (shielding) experienced by the electron from all the other electrons present

Question 8

What happens to ionisation energy across a period?

Answer 8

As you move across a period the nuclear charge increases. This leads to an increase in attraction between the nucleus and the electron, therefore decrease in the energy of the outermost electron. An increase in the first ionisation energy

Question 9

What happens to ionisation energy down a group?

Answer 9

As we go down the group the number of protons increases. This leads to an increase in attraction between the nucleus and the electron, therefore decrease in the energy of the outermost electron. An increase in the first ionisation energy