A chemist decomposes samples of several compounds. The masses of their constituent elements are listed. Calculate the chemical formula for each compound

We need to know the molar masses of every element in the given compound first.

a) 58.69 g = 1 mole of Ni

Therefore, 1.245 g = 0.0212 moles

126.9 g = 1 mole of I

Therefore, 5.381 g = 0.0424 moles

Ratio of Ni : I = 0.0212 / 0.0424 = 1 : 2

Therefore, empirical formula is NiI2

b) 137.327g = 1 mole of Ba

2.677 g = 0.0195 moles

79.90 g = 1 mole of Br

3.115 g = 0.0390 moles

Ratio of Ba : Br = 0.0195 / 0.0390 = 1 : 2

Therefore, the empirical formula is BaBr2.

c) 9.012 g = 1 mole of Be

2.128 g = 0.236 moles

32.065 g = 1 mole of S

7.557 g = 0.236 moles

15.999 g = 1 mole of O

15.107 g = 0.944 moles

Therefore, ratio of Be : S : O = 0.236 : 0.236 : 0.944 = 1 : 1 : 4

Therefore, the empirical formula is BeSO4.

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."

lol idk man i guess u gotta ask bill nye the science guy