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Chemistry Chap. 3
Atoms and Molecules
Question | Answer |
---|---|
Did many people believe in the Atomic Theory? | No. |
Law of Definite Proportions | The law that states that a chemical compound always contain the same elements in the exactly the same proportions by weight or mass. |
Law of Conservation of Mass | The law that states that mass cannot be created or destroyed in ordinary chemical and physical changes. |
Law of Multiple Proportions | The law that states that when two elements combine to form two or more compounds, the mass of one element that combines with a given mass of the other is in the ratio of small whole numbers. |
Electron | A subatomic particle that has a negative electric charge. |
Nucleus | An atom's central region, which is made up of protons and neutrons. |
Protons | A subatomic particle that has a positive charge and that is found in the nucleus of an atom; the number of protons of the nucleus is the atomic number, which determines the identity of an element. |
Neutrons | A subatomic particle that has no charge and that is found in the nucleus of an atom. |
Atomic Number | The number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element. |
Mass Number | The sum of the numbers of protons and neutrons of the nucleus of an atom. |
Isotopes | An atom that has the same number of protons (atomic number) as other atoms of the same element but has a different number of neutrons (atomic mass). |