<u>Answer:</u> The correct answer is Radium (Ra).
<u>Explanation:</u>
Energy level having highest value of principle quantum number which is 'n' will have the highest energy electrons.
For the given options:
<u>Radium (Ra):</u> The number of electrons present in this element are 88 and electronic configuration of this element is
It has 2 electrons in 's' orbital having n = 7.
<u>Neon (Ne):</u> The number of electrons present in this element are 10 and electronic configuration of this element is
It has 2 electrons in 's' orbital having n = 2.
<u>Aluminium (Al):</u> The number of electrons present in this element are 13 and electronic configuration of this element is
It has 2 electrons in 's' orbital having n = 3.
<u>Lanthanum (La):</u> The number of electrons present in this element are 57 and electronic configuration of this element is
It has 2 electrons in 's' orbital having n = 6.
Hence, the correct answer is Radium (Ra).