Combine Lead (II) nitrate with Potassium Iodide solution

Match term definition ellipse a) diagonal cross section of a cylinder circle b) diagonal cross section through the widest part of a sphere sphere c) cross section parallel to the base of a cone great circle d) shape created when a semi-circle is rotated around the y-axis triangle e) perpendicular cross section of a cone

Which of the following is not true about the atomic model of substances?

Citric acid has a ph between 1 and 3.  it is considered to be aa. weak acidb. weak basec. strong based. strong acid