| Vocab 3 |
Atomic and Molecular Structure |
| proton | A positively charged particle in an atom |
| neutron | A particle in an atom that has no charge |
| ion | A charged particle that is formed when electrons are gained or lost |
| isotopes | Atoms of the same element with different number of neutrons |
| atomic number | The number of protons in the nucleus of an atom |
| mass number | The sum of the number of protons and neutrons in an atom |
| atomic mass | The average of the masses in an element’s isotopes |
| oxidation number | A number that indicates an element’s charge |
| chemical bonds | A force that holds atoms together in molecules |
| ionic bonds | A bond formed by an electron transfer |
| electron | A negatively charged particle in an atom |
| covalent bond | A bond formed by sharing electrons |
| valence electrons | The electrons in the outermost energy levels often involved in bonding |
| periodic table | A chart in which elements are grouped according to their properties and increasing mass numbers |
| periods | The seven numbered horizontal ( > ) rows on the Periodic Table. Elements within each period have: 1- different chemical and physical properties 2- different number of electrons in the outer energy level 3- same number of energy levels |
| groups | The eighteen numbered vertical ( ^ ) rows on the Periodic Table. Elements in the same group have: 1- • similar chemical and physical properties 2- same number of electrons in their outer energy level 3- different number of energy levels |
| metals | Elements that are:1 - shiny 2- good conductors of heat & electricity 3 - malleable 4 - tend to lose electrons in chemical reactions 5 - are found on the left side of the Periodic Table |
| nonmetals | nonmetals - Elements that : 1 - lack luster (not shiny) 2 - are poor conductors heat and electricity 3 - are not malleable 4 - tend to gain electrons in chemical reactions 5 - found on the right side of the Periodic Table |
| noble gases | Relatively inactive inert elements found in group 18 |
| Law of Conservation of Mass | A law that states that in a chemical reaction, the total mass of the reactants equals the total mass of the products |
| chemical reaction | A process in which bonds break apart and combine into new kinds of matter with different properties |
| reactant | The starting substances in a chemical reaction |
| product | The new substance(s) that are formed in a chemical reaction |
| precipitate | A solid that separates from a solution |
| activation energy | The energy required to break the bonds in a chemical reaction |
| exothermic reaction | A chemical reaction that releases energy |
| endothermic reaction | A chemical reaction that absorbs energy |
| chemical symbol | A one or two letter abbreviation for an element |
| chemical formula | A group of symbols that shows the makeup for a compound |
Biology Lab Midterm
