Question

the numbers after the element symbol (blue boxes in picture) is called the
o subscript
o coefficient
o chemical reaction

Explanation:

In chemical formulas, subscripts are used to indicate the number of atoms of an element in a molecule. For example, in \( \text{H}_2\text{O} \), the subscript \( 2 \) after \( \text{H} \) means there are two hydrogen atoms. The numbers in the blue boxes in the given picture (assuming they are part of a chemical formula like \( 2\text{H}_2\text{O} \)) - the \( 2 \) after the element symbol (if it's in a formula like \( \text{O}_2 \) for oxygen molecule) is a subscript. A coefficient is a number in front of a chemical formula (like the first \( 2 \) in \( 2\text{H}_2\text{O} \)) that indicates the number of formula units. A chemical reaction is a process, not a number - related term for the position of numbers after element symbols.

Answer:

subscript