Atoms are indestructible and can neither be created nor destroyed.

24 11Na and 24 12Mg are isobars: These are different elements (sodium and magnesium) with the same mass number.

Both elements will have the same weight under a specific gravitational force.

14 7N and 14 6C are isobars: These are different elements (nitrogen and carbon) with the same mass number.

Isobar is a phenomenon whereby atoms have different atomic numbers but the same mass number. You can read on molecular mass and relative molecular mass here.Īlso, the discoveries of isobars have shown that the atoms of different elements are not completely different.

1 1H and 2 1H and 3 1H : Hydrogen-1, Hydrogen-2 (Deuterium) and Hydrogen-3 (Tritium) are isotopes of Hydrogen with masses of 1, 2 and 3 respectively.

35 17Cl and 37 17Cl : Isotopes of Chlorine with mass numbers 35 and 37 respectively.

Some elements exhibiting isotopy include: The mass spectrometry experiment conducted on (isotopic) atoms had given a confirmation to the existence of isotopes.

You can read on worked examples of molar mass here.īased on the above explanations, isotopes have the same number of protons (atomic number) but different number of neutrons. The mass number of an atom is defined as the sum of protons and neutrons in the nucleus of the atom. Note: The difference in the mass (mass number) of isotopes is a result of the varying number of neutrons in the nucleus of their atoms. As a result, the same element can have a different mass and density. Isotopy is a phenomenon whereby atoms of the same element have the same atomic number but different mass number. The discovery of isotopes has shown that not all atoms of the same elements are similar in every aspect. Atoms of the same element are identical to each other in every aspect because they have the same shape and mass, while atoms of different elements are different in all respect.Please read on elements and characteristics of elements here. Quarks: A quark is a fast moving energy and is comprised of both the protons and neutrons in the nucleus of an atom. Neutrons: These particles have no charge (neutral) and are found in the nucleus of an atom.Įlectrons: They are negatively charged particles that revolve round the shell of atoms. Protons: They are positively charged particles in the nucleus of an atom. All matter consists of tiny indivisible particles called atoms.īased on the discovery made by Rutherford, atoms can no longer be regarded as indivisible because they can be further divided into the followings:.In this article, we will look into these atomic theories of Dalton and their modifications. Some of the atomic theory which he postulated in 1808 had to be modified based on the discoveries of other scientists. Please read on the concept of matter here. Recall that chemistry is the study of matter and the changes they undergo. John Dalton, an English chemist is considered the father of modern chemistry because of the understanding he brought into the composition of matter and the basis for their chemical reactions.

Topics in Chemistry Avogadro's number explained with worked examples Mole and Avogadro's Number explained Le Chatelier's Principle: Changes in concentration and pressure in dynamic equilibrium Chemical Equilibrium: Dynamic Equilibrium in Chemistry Static and Dynamic Equilibrium explained with their differences Chemistry Scheme of Work, SS1, First Term Chemistry Scheme of Work, SS1, Second Term Chemistry Scheme of Work, SS1, Third Term Compounds in Chemistry: Characteristics of Compounds Types of Mixture: Homogenous and Heterogeneous Mixtures What are mixtures? Characteristics of mixtures Physical properties of matter Chemical properties of matter explained with examples Differences between physical and chemical change in chemistry Ionic Theory and Electrolysis Physical and Chemical Properties of Acids States of Matter: Characteristics of Solids Liquid state of matter: Characteristics of liquids Gaseous state of matter: Characteristics of gases Molar Mass, worked examples and

John dalton atomic theory