Chemical Elements Basic Information

Symbol Each element is assigned a chemical symbol. This symbol usually originates from its name or its Latin name. For example, silicon has a chemical symbol "Si". Each element's symbol is composed of a capital letter followed by one or two lowercase letters.

Atomic Number Each atom has an atomic number. This atomic number is equal to the number of protons in the nucleus of that particular atom. For example, the element cobalt (Co) has an atomic number of 27. This atomic number is also the number of protons in the atom. Therefore, Co has 27 protons.

Atomic Mass Unit or Number The mass of an atom, expressed in atomic mass units (AMU), is roughly equal to the number of protons plus the number of neutrons. This is because both the protons and the neutrons in an atom have a relatively equal mass. The mass of an electron is so insignificant that it is not represented in the atomic mass.

Melting Point The melting point of any element is the temperature at which the element changes from a solid to a liquid or from a liquid to a solid. Even though water is not an element, I will be using it in this example. Water freezes and ice melts at 0 °C (32 °F). Therefore, the melting point of water is 0 °C. The melting point is provided in degrees Celsius, Fahrenheit, and Kelvin. The melting point of a substance is also the freezing point.

Boiling Point The boiling point of any element is the temperature at which it changes from a liquid to a gas or from a gas to a liquid. You probably know that water changes to steam and steam changes to water at a temperature of 100 °C (212 °F). The boiling point of water is 100 °C. Therefore, the boiling point is also the condensation point. The boiling point is provided in degrees Celsius, Fahrenheit, and Kelvin.

Number of Protons/Electrons The number of protons/electrons in any atom is always equal to the atomic number of the atom. Each atom has a neutral charge, and since a proton has a positive charge and an electron has a negative charge, in order to achieve a neutral charge, the number of protons and electrons must equal. A particle that is not neutral (has either more or less electrons) is known as an ion.

Number of Neutrons The number of neutrons in an atom is equal to the number of protons in an atom subtracted from the mass of the atom rounded to the nearest integer.

Number of Energy Levels: 6 First Energy Level: 2 Second Energy Level: 8 Third Energy Level: 18 Fourth Energy Level: 32 Fifth Energy Level: 18 Sixth Energy Level: 6

Classification The classification of any element relates to its properties. Each periodic table may use different group names and classify each element a little differently. This periodic table uses 9 families: Alkali Metals Alkaline Earth Metals Transition Metals Other Metals Metalloids Non-Metals Halogens Noble Gases Rare Earth Elements

Element Type: Metalloid Family: Oxygen Period: 2 Group: 16 Element Name Polonium Atomic Number: 84 Atomic Mass: 209 Protons: 84 Neutrons: 125 Electrons: 84 Configuration: 2-8-18-32-18-6 Element Type: Metalloid Family: Oxygen Period: 2 Group: 16 Interesting Facts about Element Polonium: Ex. They use Polonium in nuclear batteries for space equipment.

Atomic Structure Number of Energy Levels- The number of energy levels refers to how many "electron shells" or places where electrons can be an element has. An element with 4 shells, such as zinc (Zn), has 4 different areas where an electron is likely to be found. Electron Arrangement- The electron arrangement of an atom refers to the number of electrons in each energy level. For example, carbon (C) has 6 electrons. Its atom arrangement shows that the six electrons are divided up into two shells, with 2 and 4 electrons, respectively. Electron Configuration- The electron arrangement described above can be further described to include information about orbitals, shells, and more. This explanation is beyond the scope of this document, but if you are already aware of what these numbers mean, they are provided here for you. Bohr Models- On this periodic table, Bohr models are now available for all 112 known elements. These models are designed to give some idea of how the electrons are spread over the energy levels. However, the Bohr model is now considered inaccurate among most scientists. This is because Bohr models show that electrons travel on specific paths or orbitals, a theory which has now been replaced by one that states that an electron has a greater probability of being in a certain area (or "energy level") of the atom.