Hydrogen would be my educated guess, considering it is the simplest and most abundant element in the universe.
The second element in a chemical equation is typically the element to the right in the equation following the first element. The second element will combine with the first element to form a compound or molecule.
This simple form of a chemical element is the atom.
Element
An element
Berkelium is a chemical element, not first or second.
This chemical element is carbon.
This element is very reactive.
The first figure in a properly written chemical symbol represents the atomic number of the element, which is the number of protons in the nucleus of an atom. The atomic number defines the element's identity and determines its unique chemical properties.
Neon (Ne) is a chemical element that comes in gas form.
A chemical compound is formed.
Elemental form refers to the pure, basic form of an element that consists of only atoms of that element. It is the simplest and most basic form in which an element can exist, with no chemical combination with any other element.
Helium is a gaseous chemical element.