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)

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)

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)

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