The compound C2E10H12 (where E is an element) has a formula mass of approximately 144 g/mol. What is the atomic mass of E?

Explanation:

C₂E₁₀H₁₂  = 144

molecular weight of given compound

= 2 x 12 + 10 x E + 12 x 1 = 144 ( atomic weight of C = 12 , H = 1 , E = E )

24 + 10 E + 12 = 144

10 E = 108

E = 10.8

Atomic mass of E = 10.8 u .

since the atomic number is the number of protons in the nucleus, as we move to the left on the periodic table, the electrostatic pull between the nucleus and the valence electron shell decreases. as we move down a group (vertical column), the valence shell energy level gets further and further from the nucleus.

2b2t

explanation:

2b2t