Chapter 1 - Atomic structure and the Periodic Table (L)

Question 1

What is the relative mass of an electron?

Answer 1

1/1840

Question 2

What is the order of electron sub shells?

Answer 2

S, P, D

Question 3

What does a mass spectrometer do?

Answer 3

Measure the masses of atoms and molecules

Question 4

What is the definition of relative atomic mass?

Answer 4

The weighted mean mass (average) of an element relative to 1/12 of the mass of an atom of carbon-12

Question 5

What is the definition of relative isotopic mass?

Answer 5

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

Question 6

What is the relative isotopic mass of carbon-12?

Answer 6

12

Question 7

What is the molecular ion peak?

Answer 7

The peak with the highest m/z ration in the mass spectrum

Question 8

How many electrons can an S sub shell contain?

Answer 8

2

Question 9

How many electrons can a P sub shell contain?

Answer 9

6

Question 10

What is the difference between sub shells and orbitals?

Answer 10

Orbitals are within sub shells- e.g. there are 3 orbitals in the P sub shell, which each contain 2 electrons

Question 11

What is the main exception to the filling of sub shells?

Answer 11

4s comes before 3d

Question 12

Why do orbitals sometimes partially fill both rather than fully fill one and leave another with only 1?

Answer 12

Because half filled sub shells are relatively stable, so the atom is more stable if both are half filled rather than 1 fully filled and the other not- e.g. the 4s orbital sometimes only fills with 1 electron (half), in order to allow the 3d sub shell to fill either 5 (half) or 10 (full)

Question 13

What is Hund’s rule?

Answer 13

States that electrons will prioritise occupying the orbitals singly before pairing

Question 14

What is the Pauli Exclusion Principle?

Answer 14

States that two electrons cannot occupy the same orbital without opposite spins

Question 15

What are the 3 orbitals in the P sub shell referred to as?

Answer 15

X,Y+Z

Question 16

What is the probability of finding an electron within the boundaries of S and P orbitals?

Answer 16

90%

Question 17

What is first ionisation energy?

Answer 17

The energy required to remove an electron from each atom in one mole of atoms in gaseous state, to give one mole of gaseous 1+ ions

Question 18

What are the 4 main factors affecting first ionisation energy?

Answer 18

• Nuclear charge
• Distance between nucleus and electron
• Electron shielding
• Whether the electron is on its own in an orbital or paired with another electron

Question 19

What is the effect of increased electron shielding?

Answer 19

Decreased ionisation energy

Question 20

How does ionisation energy differ from when an electron is on its own in an orbital to when it’s paired with another electron?

Answer 20

When an electron is paired with another electron in an orbital, this can cause a repulsion between the two, lowering ionisation energy

Question 21

What is the s-block?

Answer 21

Group 1-2

Question 22

What is the d-block?

Answer 22

Transition metals

Question 23

What is the p-block?

Answer 23

Group 3-8

Question 24

What is periodicity?

Answer 24

The repeating pattern of atomic, physical and chemical properties with increasing atomic number

Question 25

What happens to the atomic radius as you go across each period and why?

Answer 25

It decreases, as the nuclear charge is increasing, so there is a greater attractive force between the nucleus and outer electrons

Question 26

Why is there an anomaly in ionisation energy between B and Be, and Mg and Al?

Answer 26

Because in B, the outer electron is in a 2p orbital as opposed to a 2s orbital for Be, meaning it has more energy and so the energy required to remove it is less. This is the same for Mg and Al, except it is 3s and 3p orbitals involved.

Question 27

Why is there an anomaly in ionisation energy between N and O?

Answer 27

Because in O, there is two electrons in a single orbital, as opposed to in N, where there is only 1 in each orbital, and this increases electron-electron repulsion, therefore reducing ionisation energy

Question 28

What 2 factors affect atomic radii?

Answer 28

The radius of an atom is governed by

• the number of layers of electrons around the nucleus
• the pull the outer electrons feel from the nucleus.