Topic 1: Atomic Structure & PT

Question 1

Atomic Number

Answer 1

Number of protons in the nucleus of an atom

Question 2

Mass Number

Answer 2

Sum of number of protons and neutrons in the nucleus of an atom

Question 3

Nuclear charge

Answer 3

Total charge of all protons in nucleus (same as atomic n°, increases across periods)

Question 4

Isotopes

Answer 4

Atoms of the same element with the same number of protons but different number of neutrons in the nucleus

Question 5

Relative Atomic Mass

Answer 5

Average mass of an atom of an element relative to 1/12th of the mass of an atom of C-12

Question 6

Relative Molecular Mass

Answer 6

Average mass of a molecule relative to 1/12th of the mass of an atom of C-12

Question 7

Relative Isotopic Mass

Answer 7

Average mass of an atom of an isotope relative to 1/12th of the mass of an atom of C-12

Question 8

Quantum shells

Answer 8

Electron shells which specify energy level of an electrom

Question 9

First ionisation energy

Answer 9

The energy required to remove 1 mole of electrons from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions

H(g) -> H+(g) + e-

Question 10

Orbital

Answer 10

A region in space where one is likely to find an electron.
Can hold up to 2 with opposite spins.

Question 11

Periodicity

Answer 11

Regularly repeating pattern of atomic, chemical and physical properties along periods of the table as atomic number increases
(Ionisation energies, mp, atomic radii)

Question 12

Hund’s rule

Answer 12

When electrons fill orbitals they fill up in one direction before they start in the other
e.g: ¡¡¡ -> ¡!¡¡
-> ¡!¡!¡ -> ¡!¡!¡!

Question 13

Energy trends across period

Answer 13

Increase as nuclear charge & electrostatic attraction increase because there are more protons in the nucleus while the electrons are in the same quantum shells

Question 14

Energy trends down a group

Answer 14

Decrease as there is greater shielding and more repulsion because the outer shell is further away from the nucleus

Question 15

Atomic radii

Answer 15

half the distance between the nuclei of two covalently bonded atoms

Question 16

Atomic radii trends across period

Answer 16

Decreases as nuclear attraction is larger and e- are added to same shell, so outer shell is pulled in more tightly with minimal shielding

Question 17

Trend in melting and boiling point

Answer 17

Metals: strength of bonds increases as ion size decreases and charge increases which take more energy to break
Giant covalent: highest, strong covalent bonds
London forces: weak intermolecular forces easy to overcome

Question 18

Mass Spectometry

Answer 18

tells us the relative isotopic masses and abundances of different elements
to work out mr from a graph:
1. Multiply each mass by its abundance and add up
2. Divide by sum of abundances