| A | B |
|---|
| Atomic mass | The average mass of 1 atom of the element |
| Periodic table | A chart of the elements showing the repeating pattern of their properties |
| Nucleus | The central core of one atom containing protons and usually neutrons |
| Protons | A small positively charged particle in the nucleus of the atom |
| Neutron | A small particle in the nucleus of the atom with no electrical charge |
| Electrons | A tiny negatively charged particle that moves around the nucleus of an atom |
| Atomic mass unit | A unit used to measure the mass of particles in atoms: a proton or a neutron has a mass of one AMU |
| Atomic number | The number of protons in the nucleus of an atom |
| Chemical symbol | A one or two letter representation of an element |
| Group | Elements in the same vertical column in the periodic table. They are also called families. They have something in common and are usually named after the element on the top row. |
| Period | A horizontal row of elements in the periodic table. |
| Valance electrons | The farthest electrons rom the nucleus of the atom. They re involved in chemical reactions (share or share) |
| Malleable Material | A physical property of a metal… can be pounded into shape (molded) |
| Ductile | A physical property of a metal… can be pulled out or drawn into a long wire. |
| Conductors | A physical property of a metal… can transmit heat and electricity easily |
| Magnetic | A physical property of a metal… attracted to magnets and can be made into magnets |
| Reactivity | The ease and speed in which an element or compound combines with other elements or compounds |
| Alloy | A mixture of metals |
| Alkali metals | Group 1: They are so reactive, they are never found uncombined in nature. They are very shiny and soft. (Sodium and Potassium, lithium) |
| Alkaline earth metals | Group 2: Never found uncombined. Bright white, fairly hard, and good conductors of electricity |
| Transition Metals | Group 3-12: form a bridge between the highly reactive metals on the left, and the less reactive metals on the right of the periodic table. They are hard and shiny; some have different colors, good conductors of electricity. React slowly or not at all with air and water. (Iron, copper, nickel, silver, and gold) |
| Metals and Mixed Groups | Group 13-16: Metals, no-metals, and metalloids. They are not very reactive. (Aluminum, tin, and led) |
| Lanthanides | The elements on the bottom of the periodic table. They are soft, malleable shiny metals with high conductivity. They are used to make various alloys. |
| Actinides | The elements on the bottom of the periodic table. Only Thorium and Uranium exist on earth in small amounts. These elements are made artificially in laboratories. Their nucleus is very unstable. |
| Nonmetals | Elements that lack the properties of metals. They are 17… |
| Low boiling points | Physical characteristic of nonmetals: hydrogen and oxygen |
| Dull | Physical characteristic of nonmetals: not shiny |
| Brittle | Physical characteristic of nonmetals: they break easily. They nonmalleable or nonductile |
| Non conductors | Physical characteristic of nonmetals: they are not good conductors of heat or electricity. |
| Group 18 nonmetals | Their valance electrons are stable, so they don't react with others |
| Compounds of nonmetals | Metals and nonmetals, or nonmetals and nonmetals can combine to form compounds |
| Diatonic molecules | Molecules of 2 identical atoms |
| Carbon Family | Group 14: Atoms with four valence electrons. One of the elements is a nonmetal and that element is carbon itself. It is essential for all living things |
| Nitrogen Family | Group 15: Atoms with 5 valence electrons. The two nonmetals in the family are nitrogen, which doesn't readily react with other elements and phosphorus. This gas fills up 80% of the atmosphere. |
| Oxygen Family | Group: 16 Atoms with 6 valence electrons. They are highly reactive (oxygen to breath, sulfur bad smell, and selenium in medicine) |
| Halogen Family | Group 17: (fluorine, chlorine, bromine, iodine, and astatine) 7 valence electrons and usually only shares one when it reacts. They are very reactive and dangerous to humans, but their compounds are very useful. |
| Noble Gasses | Group 18: they don’t from compounds with other elements. They don’t gain, lose, and share their valance electrons. They are very stable and unreactive. They are not very popular but can be seen in balloons filled with helium and also neon lights. |
| Hydrogen | The simplest element with only 1 proton, and 1 electron, so simple that it cannot be grouped with any other. However, 90% of this atom fills the universe. |
| Metalloids | Have some of the characteristics of metals and some of the nonmetals. The most common is silicon. They are used to make semiconductors. |
| Semi-conductors | Under some conditions carry electricity, while under conditions it can’t. |
| Plasma | A state a matter in which atoms are stripped of their electrons and the nuclei are packed close together |
| Nuclear Fusion | Atomic nuclei combine to form a larger nucleus releasing huge amounts of energy in the process |
| Supernova | A tremendous explosion that breaks apart a massive star, producing temperatures up to 1 billion degrees Celsius |
