Question

what are isotopes? how does the exitence off isotopes contradict Dalton's atomic theory?​

Answer 1

Answer:

one of two or more forms of a chemical element that have different physical characteristics but the same chemical characteristics

Explanation:

Yes, Dalton’s theory is contradicted. This is because Dalton’s theory says that all matter is composed of atoms which are identical, indivisible, and indestructible. Isotopes consist of the same element, but have a different number of neutrons. Since isotopes are the same element, clearly protons and neutrons must be different, because if they were the same every time you added another neutron it should change elements because it would have a different atomic number. Since this is NOT the case because the element remains the same Dalton’s theory is contradicted.

Answer 2

Atoms of an element must have the same atomic number, but their mass number can be different due to the presence of different number of neutrons. These atoms of an element having different number of neutrons are called isotopes.

Explanation :

According to Dalton's theory, all atoms of an element are similar to all respects, for example, they have the same shape, size etc. and have similar physical and chemical properties like mass, density and reactivity. Whereas isotopes of an element have atoms that are similar as they have same number of protons and electrons but differ in the number of neutrons. So, the isotopes have atoms that are not similar in all aspects