Topic 1 - Atomic Structure and the Periodic Table

Question 1

Proton

Answer 1

Relative charge: +1
Relative mass: 1

Question 2

Neutron

Answer 2

Relative charge: 0
Relative mass: 1

Question 3

Electron

Answer 3

Relative charge: -1
Relative mass: 1/1836

Question 4

Isotopes

Answer 4

atoms of the same element (same number of protons) with different numbers of neutrons

Question 5

Ions

Answer 5

positively or negatively charged atom or group of atoms
formed when atoms gain or lose electrons

Question 6

Mass spectroscopy

Answer 6

an analytical technique that provides an accurate way of measuring the mass of atoms and molecules

Question 7

Mass spectroscopy steps

Answer 7

1. Ionisation
   Electrons fired from the electron gun knock electrons free from neutral particles, making them positively charged
2. Acceleration
   Negatively charged plates keep the positively charged ions moving
3. Deflection
   Two negatively charged electromagnets deflect the cations so that they change direction
4. Detection
   The detector is capable of distinguishing charged particles falling onto it

Question 8

Mass spectrum

Answer 8

shows the mass of all the isotopes and the relative amount of each

Question 9

Atomic orbital

Answer 9

a region around the nucleus that can hold up to two electrons with opposite spins (one clockwise one anti)

Question 10

Subshell

Answer 10

all of the orbitals of the same type in the same shell

Question 11

Ionisation energy

Answer 11

the amount of energy required to remove one mole of electrons from one mole of gaseous atoms or ions

Question 12

First ionisation energy

Answer 12

the amount of energy required to remove one mole of electrons from one mole of gaseous atoms to form X+

provides evidence for electron sub-shells

Question 13

Filling subshells (order)

Answer 13

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 4d, 4f

Question 14

Max. number of electrons in each subshell

Answer 14

s - 2
p - 6
d - 10
f - 14

Question 15

Aufbau principle

Answer 15

electrons enter the lowest energy orbital available

Question 16

Hund’s rule

Answer 16

electrons prefer to occupy orbitals on their own, and only pair up when no empty orbitals of the same energy are available

Question 17

(example) an s block element

Answer 17

has its highest energy electron in an s-orbital

e.g. lithium (1s2, 2s1)

Question 18

Periodicity

Answer 18

a repeating trend in physical and chemical properties across the different periods of the periodic table

Question 19

trend in atomic radius across a period

Answer 19

• atomic radius decreases
• number of protons increases by one per atom (as does number of electrons)
• each extra proton causes increased charge, which pulls the electrons closer to the nucleus
• no shielding as each atom has same number of shells

Question 20

trend in atomic radius down a group

Answer 20

• atomic radius increases
• each atom has an extra shell of electrons
• the outer electron therefore lies further from the nucleus
• increase in shielding as number of shells with electrons increases

Question 21

trend in ionisation energies down a group

Answer 21

• ionisation energy decreases
• atomic radii increase, so valence electrons move away from the nucleus
• although nuclear charge increases, shielding causes electrostatic force of attraction to decrease
• electron is more easily lost, meaning a lower activation energy

Question 22

trend in ionisation energies across a period

Answer 22

• ionisation energy increases
• number of shells doesn’t change
• nuclear charge increases as proton number increases
• greater electrostatic force of attraction between electrons and protons
• no shielding, so atomic radii will decrease due to stronger attraction
• losing electrons becomes harder

Question 23

why successive ionisation energies get larger

Answer 23

less shielding, lower shell, therefore more energy supply is needed for electron to escape

Question 24

electronegativity

Answer 24

power of an atom to attract two electrons in a covalent bond

Question 25

Successive ionisation energy

Answer 25

The energy needed to remove a second electron from each ion in 1 mole of gaseous 1+ ions to give gaseous 2+ ions

Provides evidence for the existence of quantum shells and the element group

Question 26

Shape of s orbital

Answer 26

sphere

Question 27

Shape of p orbital

Answer 27

dumbbell

Question 28

Atomic emission spectrum

Answer 28

The pattern of lines formed when light passes through a prism. Provides evidence for the existence of quantum shells.

Question 29

Ar equation (mass spectrometry)

Answer 29

Ar = (m/z*abundance)/total abundance

Question 30

Relative abundance (of isotopes)

Answer 30

the proportion of one particular isotope in a mixture of isotopes found in nature

E.g., relative abundance of Cl-35 and Cl-37 is 75% and 25% respectively. In nature, 75% of the chlorine atoms is the Cl-35 isotope and 25% is the Cl-37 isotope