Question

Which of the elements listed below would require the least amount of energy to remove an electron?

Sodium

Calcium

Lithium

Beryllium

Answer 1

removal of electrons means:- ionisation enthalpy and ionisation enthalpy increase in period from left to right and decrease down the group...

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.than Ur answer is calcium

Answer 2

sodium required least energy to remove electron because due to increase of energy shell level that lithium

and 2 reason is they have 1 electron in outermost shell they loose electron to become stable

and 3 reason is energy between electron and proton is not much higher that lithium , calcium and berrylium

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...I hope it is helpful to you
please mark it as brainlist..