What did John Dalton state in his atomic theory? A. Atoms are made up of smaller particles.
B. There is only one kind of atom.
C. Matter is made up of atoms.
D. Atoms are the cause of all observations in science.

C. Matter is made up of atoms.

Explanation:

John Dalton was an English chemist, physicist, and meteorologist. He is best known for his atomic theory and research about color blindness. In his honor, this condition was named daltonism.

According to Dalton's atomic theory, all matter is made up of atoms. His theory is very significant, but not perfect. He claimed that all atoms of the same element were identical and that different elements had atoms of different size and mass. Now, it's been proven that atoms of some elements vary in their masses and densities. These atoms are called isotopes (e.g. chlorine has two isotopes with mass numbers 35 and 37). Also, some atoms of different elements have the same mass. These atoms are called isobars (e.g. argon and calcium atoms each have an atomic mass of 40 AMU).

a electronegativity decreases beacuse the size of nucleus is bigger.