Answer:
Absolutely True :) cause we use it all the time
All of them are properties of compounds except III.
for I, compounds are chemically combined together, so to separate them, we must use chemical methods like electrolysis or applying heat. These requires large amount of energy.
For II, they're always fixed. For example, in water (H2O), the ratio of hydrogen and oxygen is always 1:8 in mass. If there's some extra added, the substance becomes mixture instead of compounds.
For IV, after you chemically combined elements or compounds together, their properties are completely different. For example, iron can be attracted to magnets, but iron II sulphide does not.
We have to fill the gap
The correct answer is: Metals with the largest atoms and the smallest number of valence electrons and non-metals with the smallest atoms and the greatest number of valence electrons are the most reactive.
Reactivity of any species depends on ease of release or gain of electron. The species which can release electron easily from valence shell, the species is more reactive whereas the species which can accept electron to its valence shell easily is also more reactive.
Answer:
Rubidium is a typical but very reactive member of the series of alkali metals. It is appreciably more reactive than potassium, but less so than caesium, and so would be expected to react more violently with those materials that are hazardous with potassium or sodium.
