Question: what is the maximum number of electrons in the first energy shell of an atom
[{'answer': 'two electrons', 'provenance': [{'wikipedia_id': '19916615', 'title': 'Electron shell', 'start_paragraph_id': 2, 'start_character': 88, 'end_paragraph_id': 2, 'end_character': 101, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '19916615', 'title': 'Electron shell', 'start_paragraph_id': 2, 'start_character': 0, 'end_paragraph_id': 2, 'end_character': 731, 'bleu_score': 0.9570764685495211, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 14375872857406124032}, 'section': 'Section::::Abstract.'}]}]