Answer:
2nd energy level
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The balanced equation for reaction of solid cesium with liquid water
= 2Cs + 2H2O → 2CsOH + H2
cesium react with liquid water to produce cesium hydroxide and hydrogen gas
that is 2 moles of Cs react 2 moles of H2O to form 2 moles CsOH and 1 of hydrogen gas
Answer: A) Ar
Explanation: Argon [Ar] has an atomic no of 18 and the electronic configuration is:
Ar :
Chlorine [Cl] has atomic no of 17 and thus the electronic configuration is :
Cl :
Magnesium [Mg] has atomic no of 12 and thus the electronic configuration is :
Mg :
Sodium has atomic no of 11 and thus the electronic configuration is :
Cl :
As we move across a period the number of electrons are being added to the same shell but the number of protons increases, thus the electrons are being tightly held and thus the atomic radius keeps on decreasing.
Thus the smallest atom would have a tightly bound electron nearer to the nucleus. As argon is the last element of the period, it is the smallest in the period and thus largest amount of energy will be required to remove the outermost electron.