Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Atoms, Elements and Periodic Table Quiz Study Guide 1. Atom concept—origins—Democritus and Aristotle in ancient Greece 2. John Dalton—first published atomic theory, proposed each element has a particular structure of atom. 3. J. J. Thomson—cathode ray tube experiment, discovered electron, plum pudding model of atom 4. Ernest Rutherford—gold foil experiment, discovered nucleus, positive charges to particles like protons. 5. Niels Bohr—first proposed electrons moving in energy levels. Designed the first working model of an atom with electrons. 6. Modern Atomic Theory—electron cloud model, the atom is the smallest part of an element that has the same properties as that element. Atoms are composed of protons, neutrons and electrons. Electrons move in clouds of orbitals in energy levels outside nucleus. 7. nucleus—contains protons and neutrons 8. protons—positive charged particles in nucleus 9. neutrons—neutral (no charged) particles in nucleus 10. electrons—negatively charged particles that follow orbitals around nucleus. 11. atomic number—the number of protons in an atom of an element 12. mass number—the average of the abundance of the isotopes of atoms of an element (contains both protons and neutrons). 13. isotope—an atom of an element with a different number of neutrons. 14. ion—an atom with a charge due to a different number of electrons. 15. orbital—a three dimensional shaped path that electrons follow when moving around the nucleus. Different shells of electrons contain different numbers and shapes of these orbitals. The orbitals are labeled s, p, d and f. 16. Forces in atoms: four forces are at work in all matter: gravitational force, electromagnetic force, strong nuclear force, and weak nuclear force. 17. Gravitational force—between anything with mass, very small in atoms. 18. Electromagnetic force—attraction between opposite charges keeps electrons bound to nucleus of atoms. Without it, we would not have atoms. 19. Strong force—between larger particles when close together—overcomes the repulsive electromagnetic force between protons in nucleus to hold the nucleus together—without it, we would not have any atoms. 20. Weak force—between particles that can decay and become other particles. Without it, radiation would not work and energy could not be exchanged between particles, thus, no atoms. 21. Dmitri Mendeleev—Russian chemist who first conceived of the Periodic Table of Elements. 22. Periodic Table of Elements—an arrangement of elements by increasing atomic number and by similar properties based on their VALENCE. Using this table, the metals are on the left, the non-metals on the right, divided by a stair step line which contains the metalloids (between metals and non-metals). 23. Metals—give up electrons-good conductors. 24. Non-metals—accept electrons—good insulators. 25. Metalloids—in between—semi conductors—make good materials for digital devices. (Like Silicon). 26. Periods—rows of the Periodic Table that correspond to the filling of a particular electron shell. 27. Family/Group—a column of the Periodic Table that includes elements with the same VALENCE, thus making them interact in similar ways with other elements (combine into similar compounds.) The maximum number of electrons in a shell typically increases with distance away from the nucleus of the atom. The Valence repeats in a periodic pattern, thus we have a “Periodic” Table of elements. 28. Unusual elements—Hydrogen and Helium can react differently from other elements due to their small size and different structure, thus they are often removed from the other part of the table and set apart. 29. Valence—the number of electrons in the outer shell of an atom of an element. It determines how an atom will interact with other atoms. 30. Atom stability—atoms want to be stable and balanced—they prefer to have either a full or empty outer shell of electrons. 31. Valence and Family of Elements—Each family of elements has a particular valence number that determines its reactivity with other elements. 32. Alkali Metals—Group 1 metals that have a high reactivity, and can explode violently when reacted with water or other substances. 32. Alkaline Earth Metals—Group 2 metals that are reactive, and tend to bond with two elements or in double bonds. 33. Halogens—Group 17 non-metals that like to bond with the Alkali Metals to form compounds. They are good insulators. 34. Inert (Noble) Gases—Group 18 elements that tend to not react much due to their full outer shells of electrons. Includes Helium, Neon, Krypton, etc. used in advertising signs. 35. Transition Metals—the middle groups 3-11 in the Periodic Table including copper, gold, silver, zinc, etc. They can form multiple bonds and sometimes have two unhappy outer shells of electrons. They often combine into alloys of two or more metals together (examples—gold and silver jewelry.)