Hello,

As He+ becomes H after removal of electron and probable of finding an electron by multiplying the square of the wave function of the spherical is orbital . so the most probable radius is 26.5 pm as it sums up when surface area is being used instead of volume .

Hope this helps you .

Bohr’s model includes a small positively charged nucleus in center which is  surrounded by negatively charge electrons moving around the nucleus in orbits. Bohr model showed that the energy of an electron was inversely dependent on the distance between the center(nucleus) and the electron.

Postulates of Bohr's Model of an Atom:

• In an atom negative electrons revolve around positive charge nucleus in a fix circular path which are called as orbits.
• Each orbit has a fixed energy and these circular orbits are known as orbital shells.
• The energy level of these orbits are represented using quantum numbers which are integers(n=1,2,3,4...). This range of quantum number starts from nucleus with n=1 having the lowest energy level. The orbits n=1, 2, 3, 4… are assigned as K, L, M, N…. shells and when an electron attains the lowest energy level it is said to be in the ground state.
• The electrons in an atom move from a lower energy level to a higher energy level by gaining the required energy and an electron moves from a higher energy level to lower energy level by losing energy.

Hope this helps you,

Thank You.

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HI there,

Could please mention for which exam you want to take the mock tests,

kindly mention the exam name so it is better to answer you clearly