Texas TEKS Standards
TX.112.20. Science, Grade 8.
(8.5) Matter and energy. The student knows that matter is composed of atoms and has chemical and physical properties. The student is expected to:
8.5 (B) Identify that protons determine an element's identity and valence electrons determine its chemical properties, including reactivity.
8.5 (D) Recognize that chemical formulas are used to identify substances and determine the number of atoms of each element in chemical formulas containing subscripts.