2.1-2.3 notebook notes

When projectiles Bounced off tissue paper: The Rutherford model of atomic structure

• Particles made of Subatomic particles: the neutrons, protons, and electrons in an atom

• Discovery of first subatomic particle occurred in 1897 by physicist Joseph John Thomson

• Cathode rays: streams of electrons emitted by the cathode in a partially evacuated tube

  • invisible to naked eye

• Thomson called particles corpuscles but are now known as electrons: a subatomic particle that has a negative charge and negligible mass

• Particles of matter can lose and gain electrons

• Like charges repel each other and opposite charges attract\

• Radioactivity: the spontaneous emission of high-energy radiation and particles by materials

• Beta particles: a particle that is emitted during radioactive decay and is equivalent in mass and charge of a high-energy electron

• Alpha particles: a particle that is emitted during radioactive decay and is equivalent in mass and charge to a 4He nucleus

• Protons: a subatomic particle in the nuclei of atoms that has a positive charge and a mass number of 1

• Neutrons: an electrically neutral (uncharged) subatomic particle with a mass number of 1

• Unified atomic mass units (u): the unit used to express the relative masses of atoms and subatomic particles; it is exactly 1/12 the mass of 1 atom of carbon with 6 protons and 6 neutrons in its nucleus

• Daltons (da): a unit of mass equal to 1 unified atomic mass unit

2.2: Nuclides and their symbols:

• Isotopes: atoms of the same elements that have the same number of protons but have different numbers of neutrons so atomic mass is different

• Elements: matter composed of atoms all having the same number of protons in their nuclei

• Atomic number (Z): the number of protons in the nucleus of an atom

• Mass number (A): the number of protons in the nucleons of an atom

  • Nucleons (neutrons and protons): a proton or neutron in a nucleus

• Isotopes of a given element have the same atomic number but different mass numbers

2.3: Navigating the Periodic Table:

• Russian chemist Dmitri Mendeleev was the forerunner of the modern periodic table of the elements

  • Periodic table of elements: a chart of the elements in order of their atomic numbers and in a pattern based on their physical and chemical properties

    • Arranged in seven horizontal rows (periods) and 18 columns (groups or families)

    • Arranged as metals, nonmetals, and metalloids

      • Metals: elements that are typically shiny (minus mercury), malleable, ductile solids that conduct heat and electricity well and tend to form positive ions

      • Nonmetals: elements with properties opposite those of metals, including poor conductivity of heat and electricity

      • metalloids: elements that tend to have physical properties of metals but chemical properties of nonmetals

    • Main group elements/representative elements: the elements in groups 1, 2, and 12-18 of the periodic table

    • Transition metals: the elements in groups 3-12 of the periodic table

    • Noble gases: elements in group 18 of the periodic table

      • Called that because they do not interact with other elements

    • Cations: a positively charged ion

      • Group 1 +1, Group 2 2+, elements in group 3 and 4 commonly form monatomic ions with 3+ and 4+; groups 11, 12, and 13 commonly form 1+, 2+, and 3+ ions, respectively

    • Anions: a negatively charged ion

      • groups 15, 16, and 17 form monatomic ions with charges of 3-, 2-, and 1-, respectively

    • Radionuclides: a radioactive nuclide, that is found with isotopes of the elements with atomic numbers above 83

    • Alkali metals: an element in group 1 of the periodic table

    • Halogens: an element in group 17 of the periodic table

    • Alkaline earth metals: an element in group 2 od the periodic table

    • Chalcogens: an element in group 16 of the periodic table

    • Noble gases: an element in group 18 of the periodic table