* Atoms are the fundamental building blocks of matter: They are the smallest unit of an element that can exist.
* Chemical reactions involve the rearrangement of atoms: Atoms are neither created nor destroyed in chemical reactions. They simply change their arrangement and bonding with other atoms.
* Conservation of Mass: The total mass of the reactants (starting materials) must equal the total mass of the products (substances formed). This is because atoms are conserved during the reaction.
Here's an analogy: Imagine you have a set of Lego blocks. You can build different structures with the same blocks, but you never create new blocks or destroy existing ones. Similarly, in a chemical reaction, the atoms are like the Lego blocks, and they are rearranged to form new molecules.
However, there are some important nuances:
* Nuclear Reactions: In nuclear reactions, such as fission or fusion, atoms can be changed. These reactions involve changes in the nucleus of the atom, resulting in the formation of different elements.
* Isotopes: While the number of protons in an atom (its atomic number) determines the element, the number of neutrons can vary. These variations are called isotopes, and they can change in chemical reactions. However, the overall number of protons remains the same, meaning the element itself doesn't change.
In summary: Atomic Theory states that atoms are conserved in chemical reactions. They are rearranged and bonded differently, but their fundamental identity remains unchanged.
