The strength of metallic bonding is determined by the electrostatic attraction between the metal cations and the sea of delocalised electrons.
Which of the following lists the metallic elements in order of increasing strength of metallic bonding?
K<Na<Mg\text{K} < \text{Na} < \text{Mg}K<Na<Mg
Mg<Na<K\text{Mg} < \text{Na} < \text{K}Mg<Na<K
Na<K<Mg\text{Na} < \text{K} < \text{Mg}Na<K<Mg
Mg<K<Na\text{Mg} < \text{K} < \text{Na}Mg<K<Na
