A hypothetical element, E has two stable isotopes. E-38=38.012u 75.68% E-46=45.981u 24.32% The element's atomic mass would be closest to which of the elements? i) K ii) Ar iii Ca iv ) Sc V ) Cl a. iii b. overrightarrow (n) c. surd d. overrightarrow (i) e N

To find the atomic mass of element E, we need to calculate the weighted average of the atomic masses of its isotopes.<br /><br />The weighted average is calculated by multiplying the atomic mass of each isotope by its respective abundance (expressed as a decimal) and then summing up these values.<br /><br />For isotope E-38:<br />Atomic mass = 38.012u<br />Abundance = 75.68% = 0.7568<br />Weighted average contribution = 38.012u * 0.7568 = 28.82u<br /><br />For isotope E-46:<br />Atomic mass = 45.981u<br />Abundance = 24.32% = 0.2432<br />Weighted average contribution = 45.981u * 0.2432 = 11.18u<br /><br />Now, we add up the weighted average contributions of both isotopes to find the atomic mass of element E:<br />Atomic mass of E = 28.82u + 11.18u = 40.00u<br /><br />Comparing the atomic mass of element E (40.00u) with the atomic masses of the given elements:<br />i) K = 39.10u<br />ii) Ar = 39.95u<br />iii) Ca = 40.08u<br />iv) Sc = 44.96u<br />v) Cl = 35.45u<br /><br />The atomic mass of element E (40.00u) is closest to the atomic mass of calcium (Ca) with an atomic mass of 40.08u.<br /><br />Therefore, the correct answer is:<br />a. $iii$