Module 2: Foundations In Chemistry

Question 1

What are isotopes?

Answer 1

Atoms of the same elements that have the same proton number but different numbers of neutrons and therefore mass numbers

Question 2

What is relative isotopic mass?

Answer 2

The mass of an atom of an isotope of an element compared with 1/12th of the mass of an atom of carbon-12, which has a mass of 12

Question 3

What is relative atomic mass?

Answer 3

The weighted average mass of an atom’s isotopes of an element compared with 1/12th the mass of an atom of carbon-12, which has a mass of 12.

Question 4

What is an atomic orbital?

Answer 4

A region of space around the nucleus that can hold up to 2 electrons with opposite spin

Question 5

How many orbitals can each sub shell hold?

Answer 5

s=1
p=3
d=5
f=7

Question 6

What is a molecule?

Answer 6

The smallest part of a chemical compound that can exist while retaining the chemical properties of that compound

Question 7

What is a dative covalent bond?

Answer 7

A bond in which all the electrons shared are provided from only one of the two atoms

Question 8

What are the two factors that affect the bonding angles and geometry of covalently bonded compounds?

Answer 8

The existence of lone pairs of electrons and the amount of covalent bonds.

Question 9

What is electronegativity?

Answer 9

The attraction between a bonded atom and the pair of electrons in a covalent bond

Question 10

How is mass spectrometry used to find the abundance of isotopes of an element

Answer 10

1. The atoms are sent through an ionisation area, where they are each vaporised and turned into positive ions
2. The ions then go through the acceleration area, where a negative field makes them accelerate
3. They then slow down in the drift area, with the ions of each isotope slowing down at different times due to their weight
4. The different isotopes will hit the ion detector at different times, and it can determine how many of each isotopes are in the group, therefore calculating the isotope abundance

Question 11

What are the 3 types of intermolecular forces?

Answer 11

Permanent dipole-dipole interactions, induced dipole-dipole interactions and hydrogen bonding

Question 12

What are permanent dipole-dipole interactions?

Answer 12

When the delta positive side of a polar molecule is attracted to the delta negative side of another polar molecule

Question 13

What are induced dipole-dipole interactions and what factors affects their strength?

Answer 13

In atoms and molecules the electrons are always moving, causing the delta negative end to change positions. This causes London forces. The more electrons there are, the larger the dipoles and therefore the stronger the London forces

Question 14

What are hydrogen bonds?

Answer 14

A type of permanent dipole-dipole that exist between a hydrogen and an atom with a lone pair. They are the strongest type of intermolecular force

Question 15

What happens when a metal reacts with an acid, oxygen or water?

Answer 15

Metal + oxygen = metal oxide
Metal + water = metal hydroxide + hydrogen
Metal + acid = salt + hydrogen

Question 16

When a metal reacts with an acid, what is oxidised and what is reduced?

Answer 16

The metal is always oxidised, the hydrogen in the acid is always reduced

Question 17

What is a disproportionation reaction?

Answer 17

When a species is both oxidised and reduced, for example, chlorine is both oxidised and reduced in the reaction Chlorine + water = hydrochloric acid + hypochlorous acid