Ionization energy is the energy needed to eject an electron from an atom or ion. Calculate the ionization energy, I E , of the one‑electron ion He + . The electron starts in the lowest energy level, n = 1 .

Ionization energy of is 54.4 eV.

Explanation:

where,

= energy of  orbit

n = number of orbit

Z = atomic number

Energy of n = 1 in an hydrogen like atom:

Energy of n = ∞ in an hydrogen like atom:

Ionization energy of =

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.