A chemical element, or an element, is defined as a material which cannot be broken down or changed into another substance using chemical means. Elements may be thought of as the basic chemical building blocks of matter. The atom is the smallest (stable) unit of matter, and therefore, of every element as well. The exact atom, corresponding to a particular element will have different protons in the nucleus, relative to other elements. However, the smallest (stable) unit of an element is the atom.
- An Element Is Made Up Of How Many Atoms
- An Element Is Made Up Of Identical Atoms
- An Element Is Made Up Of One Atom
Elements and Atoms
An element is a pure substance. It cannot be broken down into other types of substances. Each element is made up of just one type of atom.
An Element Is Made Up Of How Many Atoms
Structure of an Atom
An atom is the smallest particle of an element that still has the properties of that element. Every substance is composed of atoms. Atoms are extremely small, typically about a ten-billionth of a meter in diameter. However, atoms do not have well-defined boundaries, as suggested by the atomic model shown in figure (PageIndex{2}). An atom is composed of my subatomic particles. We will only discuss protons, neutron, and electrons.
| Particle | Proton | Neutron | Electron |
|---|---|---|---|
| Electric Charge | +1 | 0 | -1 |
| Location | Nucleus | Nucleus | Outside the nucleus |
| Mass | 1 amu | 1 amu | ~0 amu |
If the number of protons and electrons in an atom are equal, then an atom is electrically neutral because the positive and negative charges cancel out. If an atom has more or fewer electrons than protons, then it has an overall negative or positive charge, respectively, and it is called an ion.
The negatively charged electrons of an atom are attracted to the positively charged protons in the nucleus by a force called electromagnetic force, for which opposite charges attract. Electromagnetic force between protons in the nucleus causes these subatomic particles to repel each other because they have the same charge. However, the protons and neutrons in the nucleus are attracted to each other by a different force, called nuclear force, which is usually stronger than the electromagnetic force repelling the positively charged protons from each other.
Periodic Table of the Elements
An Element Is Made Up Of Identical Atoms
An Element Is Made Up Of One Atom
There are almost 120 known elements. As you can see in the Periodic Table of the Elements shown in Figure (PageIndex{3}), the majority of elements are metals. Examples of metals are iron (Fe) and copper (Cu). Metals are shiny and good conductors of electricity and heat. Nonmetal elements are far fewer in number. They include hydrogen (H) and oxygen (O). They lack the properties of metals. The element most important to life is Carbon (C). Find carbon in the table. What type of element is it, metal or nonmetal?