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A tiny particle that is the fundamental building block of substances. The properties of the atom determine the properties of the element made up only of those atoms. |
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| Dalton thought that atoms were solid little balls that could not be broken into smaller parts. Dalton found that substances always combine in the same way. He reasoned that this was because the atoms in a substance were always the same. He also thought that some materials were made of only one kind of atom, and he called these materials elements. Dalton also found that atoms seemed to combine in small, whole-number ratios. |
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A type of atom, with a particular number of protons in the nucleus; a pure substance with only one type of atom throughout
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| J.J. Thomson conducted experiments that led him to believe that there were negatively charged particles inside the atom. The Plum Pudding model, it was named after a muffin, it was a postive shell with little negative charged particles (electrons) throughout. |
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A negatively charged particle with much less mass than protons and neutrons (approximately 1/2000), found around the nuclei of atoms.
They determine the chemical properties of atoms
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| Rutherford said the positive charge that balanced the negative charge of the electrons was located in particles called protons.He also concluded that atoms contained one proton for each electron. He created the idea of the nucleus and the empty space around it. Discovered the neutron. He invented the planetary model, nucleus in the center and the eletrons going around it on a designed track. |
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a neutral particle with approximately the same mass as a proton, found in nuclei of atoms along with protons
The number of neutrons in the nuclus are about the same as the number of protons. |
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| Most of an atom's mass is in its nucleus where positively charged protons reside with neutrons that have no charge. Circling the nucleus are negatively charged electrons. In an electrically neutral atom, there are the same number of protons and electrons. |
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the number of protons in every atom of an element |
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| One of two or more atoms of the same element that have the same number of protons but different numbers of neutrons. |
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| all atoms are isotopes. When we refer to a material as an isotope, we mean that all its atoms have the same number of neutrons. When we refer to a material as an element, we mean that all its atoms have the same number of protons regardless of any differences in the number of neutrons. |
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| The measure of the mass of an atom, generally the sum of the protons and neutrons; this term is used when referring to a single atom or atoms of a single isotope |
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Atomic Masses of Elements
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If we know the atomic number and the atomic mass of an atom, we know how many protons and neutrons are in its nucleus.
Protons = atomic number.
Neutrons = atomic mass minus atomic number. |
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Isotopes: Stable or Radioactive?
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| he unstable isotopes may stick around for a while, depending on how unstable they are, but eventually break apart to form smaller elements. This is called RADIO ACTIVE DECAY |
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| In ancient times, the only elements that could be found or made in their pure form were carbon, gold, silver, iron, mercury, tin, lead, sulfur, and copper. There were about 100 more elements still to be discovered. |
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States that the properties of elements are periodic, or recurring, and are correlated to atomic numbers |
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Elements with black symbols are solids at room temperature- Elements with blue symbols are liquids at room temperature.
- Elements with red symbols are gases in room temperature.
- Elements with symbols in green are not found in nature. They are only created in a laboratory.
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| A horizontal row of the periodic table they repeat their properties once at the end of the row the properties restart. Because of that atoms within the period are not simmlar to one another. as you got o left to right they increase one eletron in the outter shell. |
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Each of the 18 vertical columns of the periodic table they are grouped together because they have the same amount of eletrons on their outer shell. |
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| A grouping of elements that share certain general characteristics |
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| The electrons in the outer shell of an atom are of special interest because they form bonds with other atoms. They decide the chemical balance of the atom. and/or the postive/negative charge. A full shell is 2 or 8 eletrons, so if they have one too many they give one away, if they have one too few they adopt one. The noble gases don't usally ever bond because they already have a full shell and have no need to adopt or give away. Group 1 and 17 trade the most because it takes up little energy, it takes less energy to give away one eletron than to give up three. Groups are called groups because, they have the same amount of eletrons in their outer shells. |
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| The smallest bit into which a chemical substance can be divided and still have the properties of that substance. Molecules of water contain hydrogen and oxygen atoms. |
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| changes in matter that involve changes in the types of molecules present, in which bonds between atoms are broken and/or formed |
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changes in matter that involve changes in the relationships among the molecules and/or in their motions, but not in the compounds or elements present |
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Substances containing atoms of two or more elements |
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properties of a substance relating to the chemical nature and reactivity of the substance
Flammability, decomposition, rust |
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the properties of a substance that can be observed without changing the chemical makeup of the substance |
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the temperature at which a liquid becomes a gas |
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the temperature at which a solid becomes a liquid |
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the mass per unit volume of a substance |
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| How fast somthing can disolove in water |
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| Able to be hammered out. Aluminum is so malleable that it can be hammered out into a thin foil |
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The passing of heat energy through a solid, liquid, or gas by collisions of molecules. When I touched the hot water pipe, thermal conduction allowed me to feel heat energy from the hot water inside. |
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| Electrons were not on a tack but they did have a area where they stayed in, those areas are called shells. (Niels Bohr) |
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| When atoms are tightly packed their mass becomes greater, and the volume decreases, and their density increases. When they are spread out their mass decreases and volume gets bigger and density is not as tight. |
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| Made the first periodic table by arranging them by atomic mass. |
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| He created the atomic number, then rearranged the periodic table as we have it today. |
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| In ancient times, the only elements that could be found or made in their pure form were carbon, gold, silver, iron, mercury, tin, lead, sulfur, and copper. There were about 100 more elements still to be discovered. |
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Developing the Periodic Table
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| Scientists wanted to illustrate the periodic law by arranging elements in a table, called a periodic table |
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states that the properties of elements are periodic, or recurring, and are correlated to atomic numbers
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- Elements with black symbols are solids at room temperature
- Elements with blue symbols are liquids at room temperature.
- Elements with red symbols are gases in room temperature.
- Elements with symbols in green are not found in nature. They are only created in a laboratory.
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