Answer:
+1, -1.
Explanation:
Ions may be defined as the molecules that contains charge in their structure. Ions that carry positive change is known as cations and ions that carry negative charge are known as anions.
The velency may be defined as the number of electrons present in the outermost shell. The +1 has the highest tendency to form cations because a little amount of ionization enthalpy is required to remove the 1 electrons. The -1 has highest tendency to form anion as it has the most negative electron gain enthalpy and can easily gains an electron.
Thus, the answer is +1 and -1.
