| Subject | Dutch | English |
| environ. | elementen uit groep I alkaline | elements of group alkaline |
| environ. | elementen uit groep I | element of group Any of the monovalent metals lithium, sodium, potassium, rubidium, caesium, and francium, belonging to group 1A of the periodic table. They are all very reactive and electropositive; alkaline (alkalimetalen) |
| environ. | elementen uit groep I alkalimetalen | element of group alkaline |
| CNC | I-element | integral element |