why metals that lose electrons easily ar more rective n the metals that lose less electrons are less reactive ??

The tendency of a metal to lose electrons gives us a clue about the reactivity of the metal. Generally it has been seen that more is the tendency of a metal to lose electrons, more reactive is the metal. Similarly a lesser tendency to lose electrons means less reactivity. When a metal loses electrons more easily, it means less energy would be required to pull out valence electron from the metal. In other words, the metal will have low value of ionisation energy. So even a small amount of energy would be sufficient to ionise the metal, thus converting it into reactive form. For example sodium, potassium, magnesium are all very reactive metals. Now compare it with a metal which has lesser tendency to lose electrons. More energy would be required to pull out the valence electron from this atom. This means that in comparison to metal with low ionisation energy, it requires more input of energy or in other words it is more difficult to convert this metal into a cation. Thus, it will have a lower reactivity. Examples include silver, gold etc.