bridge to a level: definitions

Question 1

anion

Answer 1

negatively charged ion

Question 2

atomic number

Answer 2

number of protons in the molecule (and therefore electrons in an atom)

Question 3

mass number

Answer 3

sum of protons and neutrons (electrons have negligible mass)

Question 4

empirical formula

Answer 4

the simplest whole number ratio of each element in a compound

Question 5

isotopes

Answer 5

atoms of the same element with different numbers of neutrons

Question 6

molecular formula

Answer 6

actual number of atoms of each element in an atom

Question 7

relative atomic mass

Answer 7

weighted mean mass of an atom compared to 1/12 that of carbon-12

Question 8

relative formula mass

Answer 8

weighted mean mass of the formula unit of a compound compared to 1/12 that of carbon-12

Question 9

relative isotopic mass

Answer 9

weighted mean mass of an isotope compared to 1/12 that of carbon-12

Question 10

relative molecular mass

Answer 10

weighted mean mass of a molecule compared to 1/12 that of carbon-12

Question 11

water of crystallisation

Answer 11

H2O molecules ‘trapped’ within an ionic lattice