Term | Definition |
Atom | The smallest unit of an element that maintains the properties of that element. |
Electron | A subatomic particle that has a negative charge. |
Nucleus | In physical science, an atom's central region, which is made up of protons and neutrons. |
Proton | A subatomic particle that has a positive charge and that is located in the nucleus of am atom; the number of protons in the nucleus it the atomic number, which determines the identity of the element. |
Neutron | A subatomic particle that has no charge and that is located in the nucleus of an atom. |
Electron Cloud | A region around the nucleus of an atom where electrons are likely to be found. |
Atomic Number | The number of protons in the nucleus of an toms: the atomic number is the same for all the atoms of an element. |
Mass Number | The sum of the numbers of protons and neutrons in the nucleus of an atom. |
Periodic Table | An arrangement of the elements in order of their atomic number such that elements with similar properties fall in the same column or group. |
Chemical Symbol | A one-, two-, or three-letter abbreviation of the name of an element. |
Average Atomic Mass | The weighted average of the masses of all naturally occurring isotopes of an element. |
Metal | An element that is shiny and conducts heat and electricity well. |
Nonmetal | An element that conducts heat and electricity poorly. |
Metalloid | An element that has properties of both metals and non metals. |
Group | A vertical column of elements in the periodic table; elements in a group share the same chemical properties. |
Period | In chemistry, a horizontal row of elements in the periodic table. |