Question: why group 2 elements called alkaline earth metals
[{'answer': 'named after their oxides', 'provenance': [{'wikipedia_id': '37411', 'title': 'Alkaline earth metal', 'start_paragraph_id': 22, 'start_character': 30, 'end_paragraph_id': 22, 'end_character': 54, 'bleu_score': 1.0, 'section': 'Section::::History.:Etymology.\n'}]}, {'provenance': [{'wikipedia_id': '37411', 'title': 'Alkaline earth metal', 'start_paragraph_id': 22, 'start_character': 0, 'end_paragraph_id': 22, 'end_character': 961, 'bleu_score': 0.986797956037998, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 17691532600638277632}, 'section': 'Section::::History.:Etymology.\n'}]}]