According to Bohr`s model of an atom, the number of electrons in an element`s valence shell is determined by its atomic number. The atomic number of an element represents the number of protons in its nucleus and is equal to the number of electrons in a neutral atom.

In this question, the element has an atomic number of 35. Therefore, the correct number of electrons in its valence shell would be equal to the element`s atomic number if it follows the Bohr`s model.

Option 1 suggests that the element has only 1 electron in its valence shell. However, since the atomic number is 35, this option is not correct.

Option 2 suggests that the element has 3 electrons in its valence shell. Similarly, this option is not correct as it does not match the atomic number of 35.

Option 3 suggests that the element has 5 electrons in its valence shell. Once again, this option does not match the atomic number of 35.

Option 4, which states that the element has 7 electrons in its valence shell, is the correct answer based on Bohr`s model. It matches the atomic number of 35, indicating that the element has 7 electrons in its valence shell.