Why some metals lose their shine over time but gold does not

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.

Water is important for the of cells. a: size, shape, and temperature b: temperature, color, and odor c: color, odor, and size d: shape, temperature, and color

Why dose heating increase the speed at which a solution dissolved in water