Ionic compounds generally occur between metals and non-metals due to their large electronegativity difference. You can simple go down Group 1 and Group 17 of the periodic table.
Examples:
NaCl (Sodium Chloride)
KCl (Potassium Chloride)
RbCl (Rubidium Chloride)
CsCl (Cesium Chloride)
The crystals will not be oxidised since it will be underground
Answer:
when an electron move closer to the nucleus the magnitude of energy of the nucleus increases
Answer:
I'm pretty sure its stimulus
