| A | B |
|---|
| substance | single kind of matter with a specific set of properties, pure, can be chemically combined |
| oxygen, Nickel, water | examples of substances |
| mixture | two or more substances mixed together but keeping their own properties and are not chemically combined |
| heterogeneous | mixture that does not appear the same throughout |
| suspension | type of heterogeneous mixture where small particles are present in liquid or gas and will settle out after enough time |
| sand/water, salad dressing; oil/vinegar | examples of suspension |
| heterogeneous | least mixed mixture |
| homogeneous | type of mixture that appears the same throughout |
| salad, tacos, soil, chex mix, granite | examples of a heterogenous mixture |
| colloid | type of homogeneous mixture in which the particles are mixed but not dissolved |
| solution | best mixed mixture |
| milk, fog, smoke, glue | examples of colloids |
| solution | type of homogeneous mixture when one substance dissolves in another |
| element | pure substance that cannot be broken down into any other substances by chemical or physical means |
| atom | basic particle from which all elements are made |
| salt water, iced tea, air, brass, soda | examples of solutions |
| element | simplest substance |
| atom | consists of a positively charged nucleus surrounded by a negatively charged electron cloud |
| chemical bond | force of attraction between two atoms |
| atoms | elements are different because their ______ are different |
| molecules | groups of two or more atoms held together by chemical bonds |
| compounds | pure substance made of two or more elements chemically combined in a set ratio. |
| chemical formula | compound is represented by a _________________ which shows the elements and the ratio of atoms |
| atom | smallest part of an element that has the properties of that element |
| colloid | type of mixture that has suspended particles and scatters light |
| solutions | mixture in which particles are too small to scatter light |
| liquid boils, evaporates, condenses and collects in a cooling tube | 4 steps of distillation |
| mass | how much matter an object contians |
| Democritus | person who discovered the smallest piece of matter and called it an atom |
| John Dalton | scientist that stated that atoms are indivisible and said that atoms of the same element are the same and atoms of different elements are different |
| J.J. Thomson | discovered the electron but his model of an atom did not have a nucleus and the electrons were stationary |
| Niels Bohr | scientist whose atomic model placed the electons in definite orbits around the nucleus in fixed energy levels |
| Rutherford | proposed that an atom has a dense positively charged nucleus |
| valence electrons | electrons in the outermost shell |
| in energy levels | how electons are arranged |
| atomic number | periodic table is arranged so the elements are in order of increasing _____________ |
| Alkalai metal | group in periodic table that is most reactive because it only has 1 valence electron |
| Noble gases | group or family that is non reactive because its outermost electron level is full |
| group number on periodic table | valence electrons can be determined by ____________ |
| metalloids | group of elements that have the characteristics of both metals and nonmetals. |
| alkalai metals | name of group 1 and contains elements that are soft, shiny, and white and contains the most reactive metals |
| Noble Gases | name of group 8 |
| Alkaline earth metals | name of group 2 |
| Halogens | name of group 7 |
| atomic number | information in the periodic table that indicates the number of protons in an atom |
| compound, element | two examples of pure substances |
| electrons | particles in atoms with a negative charge and that move around the nucleus |
| equal number of protons and electrons | reason that an atom has a neutral charge |
| plum pudding | model that showed that atoms have negatively charged particles |
| 8 | greatest number of valence electrons an atom can have |
| transition metals | group that contains the most number of elements |
| ductility | ability of a substance to be made into a thin wire |
| soluble | cannot be dissolved in water |
| calcium and magnesium | 2 most common alkaline earth metals |
| mass number | sum of protons and neutrons in the nucleus |
