This can be determined using the atomic number and the mass number of the element (see the concept on atomic numbers and mass numbers). The hydrogen atom (H) contains only one proton, one electron, and no neutrons. Atoms have different properties based on the arrangement and number of their basic particles.
![mass of a eutron mass of a eutron](http://crab0.astr.nthu.edu.tw/~hchang/ga1/NSMR2017.png)
The outermost regions of the atom are called electron shells and contain the electrons (negatively charged).
![mass of a eutron mass of a eutron](https://hi-static.z-dn.net/files/d4f/f6d48be2b4e5cf40fc652229de634448.jpg)
The nucleus (center) of the atom contains the protons (positively charged) and the neutrons (no charge). Atomic ParticlesĪtoms consist of three basic particles: protons, electrons, and neutrons. Many biological processes are devoted to breaking down molecules into their component atoms so they can be reassembled into a more useful molecule. For example, water is composed of hydrogen and oxygen atoms that have combined to form water molecules. Atoms combine to form molecules, which then interact to form solids, gases, or liquids. It is equal in mass to a proton or it weighs 1 amu.Īn atom is the smallest unit of matter that retains all of the chemical properties of an element.
![mass of a eutron mass of a eutron](https://i0.wp.com/cms.jackwestin.com/wp-content/uploads/2020/03/1.1-1.png)
Protons and neutrons have approximately the same mass, about 1.67 × 10-24 grams, which scientists define as one atomic mass unit (amu) or one Dalton.An atom is composed of two regions: the nucleus, which is in the center of the atom and contains protons and neutrons, and the outer region of the atom, which holds its electrons in orbit around the nucleus.