Answer:
Element
Step-by-step explanation:
The Number 1 which is Ca is a calcium element that is taking part in the chemical combination.
An element is a substance made up of one kind of atom.
Calcium is an element belong to the alkali earth metals. These group of elements are found on the second group of the periodic table.
- Calcium is a metal and it is a member of the s-block on the periodic table.
- It is combining with 2 moles of water in this chemical reaction.
- Calcium is made up of two valence electrons in its outermost shell.