Is lithium (Li) more or less reactive than beryllium (Be)? Why?

Lithium is more reactive as it has only one electron in its valance shell. Beryllium has 2 valance electrons. Lithium is more reactive as it is easier to lose oneelectron than losing two electrons.

Below!

Explanation:

Lithium (Li) is more reactive than Beryllium (Be). This is because Lithium lacks the valence electron that Beryllium has. Elements with a lower amount of valence electrons are less stable than those with full valence shells, causing it to react more easily. Because Lithium only contains 1 valence electron, it is easily transferred/given up to create bonds and form compounds.

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it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.