As you move from left to right across a period, what happens to the atomic radii?
they increase, because of the higher number of occupied energy levels.
they increase, because of the weaker attraction of electrons to the nucleus.
they decrease, because of the stronger effective nuclear charge.
they decrease, because of the increased atomic mass.

Which is a difference between molecular compounds and ionic compounds? select the correct answer below: question 5 options: molecular compounds typically form between a metal and a nonmetal, while ionic compounds typically form between nonmetals. molecular compounds result from the transfer of electrons between atoms to form ions, while ionic compounds result from the sharing of electrons between neutral atoms. molecular compounds are formed of discrete, neutral molecules, while ionic compounds are formed of large repeating arrays of opposite charges. molecular compounds have high melting points and high boiling points, while ionic

There are two steps in the usual industrial preparation of acrylic acid, the immediate precursor of several useful plastics. in the first step, calcium carbide and water react to form acetylene and calcium hydroxide: cac2 (s) + 2h2o (g) → c2h2 (g) + caoh2 (s) =δh−414.kj in the second step, acetylene, carbon dioxide and water react to form acrylic acid: 6c2h2 (g) + 3co2 (g) + 4h2o (g) → 5ch2chco2h (g) =δh132.kj calculate the net change in enthalpy for the formation of one mole of acrylic acid from calcium carbide, water and carbon dioxide from these reactions. round your answer to the nearest kj .

How many neutrons does an element have if its atomic number is 50 and its mass number is 166