Question

.
A particular atom becomes more energetically stable when it loses a single electron. It is most likely an atom of which of the following elements?


magnesium (Mg)
cesium (Cs)
fluorine (F)
boron (B)

Answer 1

when the atom acquires a more stable configuration then it becomes more energetically stable.here caesium will have an octet configuration on loosing an electron.so here it is caesium(Cs)

Answer 2

for an atom to be 'stable' with a 'stable configuration' like noble gases, it should have a full valence electron shell (ex: 2.8.8 or 2.8)

so to only need to lose a single electron, it must have an excess of only a single electron (ex:2.8.1 or 2.1)
which means it should have an outermost shell with only one electron

from the perodic table, only elements from group I (the first column) fit

hence the answer is Cs