Rubidium is a soft silvery-white metal that has two common isotopes, 85rb and 87rb. if the abundance of 85rb is 72.2% and the abundance of 87rb is 27.8%, what is the average atomic mass of ribidium?

Average atomic mass of Rb = 85.6 amu.

Explanation:

Abundance of Rb⁸⁵ = 72.2%

Abundance of Rb⁸⁷ = 27.8%

Average atomic mass = ?

Solution:

Average atomic mass of Rb= (abundance of 1st isotope × its atomic mass) +(abundance of 2nd isotope × its atomic mass)  / 100

Average atomic mass of Rb = (85×72.2)+(87×27.8) /100

Average atomic mass of Rb =  6137 + 2418.6 / 100

Average atomic mass of Rb = 8555.6 / 100

Average atomic mass of Rb = 85.6 amu.

answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.