Get Started. Ionization Energy vs. Atomic Number; Period 4 Graph; This graph shows the melting and boiling points in degrees Celsius for the first twenty elements. Loading graph Briccooo3's interactive graph and data of "Atomic Number vs. Melting Point" is a line chart, showing Melting Point, K; with Atomic # in the x-axis and Melting Point, K in the y-axis.. The x-axis shows values from -4.4081826831588975 to 93.4081826831589. Powered by Create your own unique website with customizable templates.