Atom - The smallest unit of matter that can exist of an element.

Compound - A molecule containing two or more different atoms bound together.

Element - A fundamental substance that has a unique atomic number on the periodic table.

Isotope - A different form of an element that varies by the number of neutrons in the nucleus.
Neutron - An uncharged atomic particle of mass 1.67493x10-27 . It resides in the nucleus.

Nucleus - The small, dense central region of an atom around which electrons orbit. The nucleus is made up of protons and neutrons.
Proton - A positively charged particle of mass 1.6726x10-27 . Protons reside in the nucleus.
Valence electrons - The electrons in the outermost energy shell of an atom. The configuration of these electrons determine the chemical properties of the element.

Valence shell - The highest energy shell in an atom, containing valence electrons. All interactions between atoms take place through the electrons of the valence shell.

	Creado por Xiang Lin Goh hace más de 8 años

Secondary 1 (Chemistry) Science Apunte sobre Chemistry:Atoms and Molecules Notes, creado por Xiang Lin Goh el 30/04/2016.