Term | Definition |
Atom | Is the smallest particle of an element which still retains the properties of that element |
Proton | Protons are a sub-atomic particle found in the nucleus of an element. Protons have a positive charge ( 1 amu ) |
Electron | Electrons are a sub-atomic particles found in the outer shells of an element. Electrons have a negative charge. ( 1/1840 amu ) |
Neutron | Neutrons are a sub-atomic particles found in the nucleus of an element. They have a zero/ neutral charge. ( 1 amu ) |
Atomic mass unit | Amu - unit used to measure the mass of sub-atomic particles |
Sub-Atomic Particles | Tiny particles inside an atom |
Planetary Number | The way in which electrons move about the nucleus in fixed paths called orbits or shells |
Atomic Number | Number of protons in that atoms nucleus |
Atomic Mass | The sum of the number of protons and neutrons |
N= number | N= the number of shells an atom has |
Group | Elements with similar properties are arranged under one another in vertical columns the columns are called groups |
Period | These are the horizontal rows of elements |
Alkali Metals | Are elements in group 1 |
Alkaline Earth Metal | Are elements in group 2 |
Halogens | Are elements in group 7 |
Nobel Gases | Are elements in group 8. They do not react with other elements |
Periodic Table | Arrangement of elements in order of increasing atomic number |
Isotopes | Atoms of the same element that have different numbers of neutrons in the nucleus |
Mendeleev | He was a Russian chemist who arranged all the known elements in the form of a table. Because the properties of the elements repeated themselves it is known as the periodic table |
Dalton | English scientist who put forward his theory of the atomic structure. He said atoms could not be divided into anything simpler |
Niels Bohr | Proposed that electrons orbit the nucleus in fixed paths called orbits. These orbits are called shells |
Molecule | A group of atoms joined together. It is the smallest particle of an element that can exist independently |
Octect rule | Atoms strive to have 8 electrons in their outer shell to make them stable |
Ionic bonding | A force of attraction between positive and negative ions in a compound |
Covalent bonding | When electrons are shared between atoms |
Ion | Chemically charged element |
Reduction | When an atom gains an electron |
Oxidation | When an atom loses an electron |