Matter is made up of a mixture of things called elements. Elements are substances that cannot be broken down into simpler substances. There are more than 100 known elements, and 92 occur naturally around us.
An atom is the simplest and smallest particle of matter that still has chemical properties of the element. Atoms are the building block of all of the elements that make up the matter in your body or any other living or non-living thing. Atoms are so small that only the most powerful microscopes can see them.
Atoms themselves are composed of even smaller particles, including positively charged protons, uncharged neutrons, and negatively charged electrons. Protons and neutrons are situated in the focal point of the particle, or the core, and the electrons move around the core.
All the atoms of a particular element have the exact same number of protons, and the number of protons is that element’s atomic number. An atom usually has the same number of protons and electrons, but sometimes an atom may gain or lose an electron, giving the atom a positive or negative charge. These atoms are known as ions and are depicted with a “+” or “-” sign. Ions
A molecule is any combination of two or more atoms. The oxygen in the air we breathe is two oxygen atoms connected by a chemical bond
A compound is any combination of two or more different elements. A compound has different properties from the elements that it contains. Elements and combinations of elements (compounds) make up all the many types of matter in the Universe
A chemical reaction is a process that breaks or forms the bonds between atoms of molecules and compounds
Elements are substances that cannot be broken down into simpler substances with different properties.
Elements have been organized by their properties to form the periodic table.
Two or more atoms can combine to form a molecule.
Molecules consisting of more than one element are called compounds.
Reactants can combine through chemical reactions to form products.