| A | B |
|---|
| element | pure substance that cannot be broken down into any other substances by chemical or physical means |
| molecules | groups of 2 or more atoms held together by chemical bonds |
| neutral | type of charge an atom has because the electrons equal the protons |
| alkali metals | group one is known as this |
| protons and neutrons | subatomic particles found in the nucleus which make up most of the mass in the atom |
| ion | charged atom |
| proton | subatomic particle with a positive charge |
| electron | subatomic particle with a negative charge that moves around the nucleus |
| atomic mass | sum of protons and neutrons in the nucleus; another name for atomic weight |
| isotopes | atoms of the same element that have the same number of protons but different numbers of neutrons |
| atomic number | number of protons in the nucleus |
| metals | group that contains the highest number of elements |
| chemical change | change that produces one or more new substances |
| alkaline earth metals | family name for group 2 |
| energy levels | electrons are arranged ___________ |
| nucleus | center of the atom |
| metals | group that contains the most elements |
| electron cloud | where electrons are found |
| transition metals | family name for groups 3-12 |
| alkali metals | group of metals that reacts violently with water |
| 2 | number of electrons that can be in the first energy level of an atom |
| 8 | maximum number of electrons that can be in the second energy level of atom |
| halogens | family name for group 17 |
| they are stable or non-reactive | reason noble gases are called inert gases |
| positive | type of charge in the nucleus of an atom |
| electron | particle found outside the nucleus |
| neutral or no | type of charge a neutron has |
| periodic table | chart in which atoms are arranged |
| compounds | pure substances made up of 2 or more elements chemically combined in a set ratio |
| atoms | consist of a positively charged nucleus surrounded by negatively charged electron cloud |
| chemical and physical properties | Mendeleev grouped elements according to their ______ and _______. |
| atomic mass | Mendeleev arranged the elements in order of increasing ________ |
| valence | all elements in a column of the periodic table have the same _______ |
| chemical bond | holds atoms together in a molecule |
| atomic number | the modern periodic table arranges the elements in order of increasing ___________ |
| atomic numbers | the periodic law states that the physical and chemical properties of the elements are periodic functions of their ______ |
| groups/families | names for a column of elements that have similar properties |
| similar | elements within the same goup of family have ______ properties |
| period | NAME FOR A HORIZONTAL ROW OF ELEMENTS |
| active solid | first element in a period is always an extremely ______ _______. |
| malleability | property that describes how material can be hammered or rolled into flat sheets |
| ductility | property that describes how material can be pulled or drawn into a long wire |
| group 1 | the most reactive metals are found in this group |
| silver, copper and nickeltransition metals | family of elements that includes familiar metals such as gold, silver, copper and nickel and is used to make colorful compounds of paint |
| neutron | subatomic particle with a neutral charge |
| electrons and protons | In a neutral atom, what 2 things are equal? |
| isotope | an atom with the same number of protons and a different number of neutrons from other atoms of the same element |
| atom | basic particle from which all elements are made |
| easily loses electrons, corrosive | chemical properties of metals |
| valence electrons | electrons in the outermost energy level |
| noble gas | name of group that contains the highest number of elements |
| metalloid | has characteristics of both metals and non-metals |
| luster, ductility, malleability | physical properties of metals |
| corrosive, easily loses electrons | chemical properties of metals |
| He, Ne, Ar, Kr, Xe, Rn | list of noble gases |
| Alkalai metal | group in periodic table that is most reactive because it only has 1 valence electon; group 1 |
| group number on periodic table | valence electons can be determined by ... |
| compounds | groups of two or more atoms held together by chemical bonds |
| atoms are very small | reason scientists create models to describe atoms |
