alkali metal vs alkaline metal

alkali metal and alkaline metal both are nouns.

Word	Noun	Adjective	Verb	Adverb
alkali metal	Yes	No	No	No
alkaline metal	Yes	No	No	No

As nouns, alkali metal and alkaline metal are synonyms defined as:

alkali metal and alkaline metal: any of the monovalent metals of group I of the periodic table (lithium or sodium or potassium or rubidium or cesium or francium)

alkali metal (noun)	alkaline metal (noun)
any of the monovalent metals of group I of the periodic table (lithium or sodium or potassium or rubidium or cesium or francium)	any of the monovalent metals of group I of the periodic table (lithium or sodium or potassium or rubidium or cesium or francium)