Module 2 definitions (both papers)

Question 1

Ion

Answer 1

An ion is an electrically charged particle formed by the loss or gain of one or more electrons from an atom or a group of atoms.

Question 2

Isotopes

Answer 2

Isotopes are atoms of the same element with the same number of protons and different numbers of neutrons and therefore different masses.

Question 3

Relative atomic mass

Answer 3

Relative atomic mass is the weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12.

Question 4

Relative isotopic mass

Answer 4

Relative isotopic mass is the mass of an isotope relative to 1/12th of the mass of an atom of carbon-12.

Question 5

What is empirical formula?

Answer 5

Empirical formula is the simplest whole number ratio of atoms of each element present in a compound.

Question 6

What is molecular formula?

Answer 6

Molecular formula is the actual number and type of atoms of each element in a molecule.

Question 7

What is stoichiometry?

Answer 7

Stoichiometry is the relationship between the amounts of reactants and products in a chemical reaction; this information is presented in the balanced chemical equation.

Question 8

First ionisation energy

Answer 8

The energy needed to remove 1 mole of electrons from 1 mole of gaseous atoms, to form 1 mole of gaseous 1+ ions

Question 9

Second ionisation energy

Answer 9

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