4.
is a pure chemical substance consisting of only one type
of atoms.
and
Answers
Answer:
A chemical element is a pure substance that consists of one type of atom. Each atom has an atomic number, which represents the number of protons that are in the nucleus of a single atom of that element.
If there is only one kind of atom in a molecule or crystal matrix like a metal it is an element.
If there are two kinds of atom in a molecule it is a compound. If there are two kinds of atoms in a crystal metal matrix it is a mixture and not a pure substance.
The type of atoms in a pure substance determine if the substance is compound or an element.
an atom is the most fundamental unit of matter.
Different types of atoms are defined by the number of protons in the nucleus (atomic number).
ex: 1 proton = hydrogen, 6 protons = carbon
an element is a pure substance made up of only one type of atom
SO THE ANSWER IS ELEMENT