Question: the elements in each period have the same number of
[{'answer': 'electron shells', 'provenance': [{'wikipedia_id': '86350', 'title': 'Period (periodic table)', 'start_paragraph_id': 1, 'start_character': 108, 'end_paragraph_id': 1, 'end_character': 123, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '86350', 'title': 'Period (periodic table)', 'start_paragraph_id': 1, 'start_character': 0, 'end_paragraph_id': 1, 'end_character': 629, 'bleu_score': 0.832344863285107, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 7781536601044294332}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '86350', 'title': 'Period (periodic table)', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells.', 'All elements in a row have the same number of electron shells', 'A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells. Each next element in a period has one more proton and is less metallic than its predecessor. Arranged this way, groups of elements in the same column have similar chemical and physical properties, reflecting the periodic law. For example, the alkali metals lie in the first column (group 1) and share similar properties, such as high reactivity and the tendency to lose one electron to arrive at a noble-gas electronic configuration. As of 2016, a total of 118 elements have been discovered and confirmed.']}}]}, {'provenance': [{'wikipedia_id': '2264346', 'title': 'Electron configurations of the elements (data page)', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell', 'This page shows the electron configurations of the neutral gaseous atoms in their ground states. For each atom the subshells are given first in concise form, then with all subshells written out, followed by the number of electrons per shell. Electron configurations of elements beyond hassium (element 108) are predicted.']}}]}]