The atomic mass of a atom determines by what?

Read the given expression. x = number of protons − number of core electrons which of the following explains the identity of x and its trends across a period? x is the effective nuclear charge, and it remains constant across a period. x is the screening constant, and it remains constant across a period. x is the effective nuclear charge, and it increases across a period. x is the screening constant, and it increases across a period.

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes

What is the empirical formula of c6h18o3? ch3o c2h5o c2h6o c2h5o5