The newly discovered element Xyyyillium (Xy) has two isotopes: Xy–253 (253.0) amu) and Xy–255 (255.0 amu). Given that the average atomic mass of Xy is 254.8 amu, what is the percent abundance
of each isotope? Justify your answer.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.

false it is never safe to stand on the top step of a ladder provided it is braced properly.