Answer:
monovalent or univalent
Step-by-step explanation:
Atoms with a valency of 1 are said to be monovalent or univalent atoms. The valency of an atom is the number of electrons in its outermost shell.
Elements with a valency of 1 would readily and easily lose one electron in order to achieve a stable configuration which would resemble those of the noble gases or group O elements.
On the periodic table, elements in group one are all monovalent i.e they all have one electron in their outermost shell.