Color schemes are used to create style and appeal. Colors that create an aesthetic feeling when used together will commonly accompany each other in color schemes. A basic color scheme will use two colors that look appealing together.
The addition of light blue creates an "Accented Analogous" color scheme.
Color schemes can contain different "Monochromatic" shades of a single color; for example, a color scheme that mixes different shades of green, ranging from very light (white), to very neutral (gray), to very dark (black). (Wikipedia)
Warm and cool colors can have an emotional response. Red is associated with passion, action and danger; orange with vibrancy and health; yellow with happiness, warmth and sunshine. Blues suggest space, coolness, tranquility, and melancholy.
Our emotional response to certain colors can be linked to their environmental association. For example, brown represents earthiness and harmony. Green suggest growth and is refreshing and cooling.
Purple is the finite color combining warmth and coldness, distance and closeness, and is often viewed as inspirational, religious, and soothing.