Across
- 3. [two words] charge on an ion formed by a Group 17 atom that gains one electron
- 6. mixture that appears uniform throughout
- 8. dull; poor conductors of heat and electricity; most are gases at room temperature (those that are solid are brittle)
- 9. name of element for an atom with mass number 39 containing 20 neutrons
- 11. [two words] distance from the nucleus to the outermost edge of the electron cloud
- 12. repeating at regular intervals
- 16. nucleus has the potential to break down, or decay, and change into a different element
- 17. negatively charged; almost no mass compared to protons; exist outside the nucleus; discovered by J.J. Thomson
- 20. negative ions formed by atoms gaining electrons
- 22. [two words] the arrangement of the elements in order of their atomic numbers
- 23. the rows of the table
- 25. [two words] modern periodic table is organized by arranging elements in order by this
- 26. [two words] predictable patterns in the periodic table, either down a group or across a period
- 27. positively charged region at the center of the atom, consisting of protons and neutrons packed tightly together
- 28. number of valence electrons in all elements in group 1
- 31. number of valence electrons in all elements in Group 17
- 36. his gold foil experiment and resulting atomic model show that the positively-charged regions of atoms are incredibly small
- 37. mixture in which particles are distributed uniformly throughout and are too light to settle out
- 39. [two words] describes how atoms react to form compounds that allow them to have a group of 8 valence electrons like the noble gases
- 40. ability of matter to combine chemically with other substances.
- 42. [two words] 1 type of particle; cannot be separated into simpler substances by physical or chemical means
- 44. [two words] the mass of the atom in a unit called the atomic mass unit (amu)
- 49. the minimum amount of energy that can be absorbed or released by matter
- 50. pure substance; appears on the periodic table
- 52. conducted experiments showing gases must consist of tiny, individual particles that are in constant, random motion; a given compound is always comprised of the same elements in the same whole-number ratio; different compounds consist of different elements or ratios; and, elements are made of separate, discrete particles that cannot be subdivided.
- 53. mixture in which particles are distributed throughout but are heavy enough that they will settle out
- 55. vertical column of the periodic table
- 56. [two words] a one-or two-letter designation of an element
- 57. condition of an atom’s outermost energy level that produces the greatest stability
Down
- 1. share characteristics of metals and nonmetals; semiconductors
- 2. positive ions formed by atoms losing electrons
- 3. Atomic Number of an atom with mass number 19 containing 10 neutrons
- 4. class found in left, bottom, center of periodic table
- 5. [two words] protons, neutrons, and electrons
- 7. class found in right of periodic table (except H on left)
- 9. unit of length used to measure atomic radius that is equal to one-trillionth of a meter
- 10. [two words] nonreactive, nonmetallic elements in Group 18
- 13. [two words] charge on an ion formed by a Group 2 atom that loses two electrons
- 14. appears to be only one substance, but is actually two or more substances distributed evenly amongst each other
- 15. [two words] the number of protons in an atom
- 18. [two words] an electron found in the outermost energy level of an atom
- 19. atom of the same element with a different number of neutrons
- 21. located in the nucleus; neutrally charged; mass = 1 amu
- 24. shiny; good conductors of heat and electricity; malleable; ductile
- 28. region in modern Quantum Mechanics model where an electron is most likely to be
- 29. mixture in which different components are visible
- 30. [two words] quarks and gluons
- 32. first proposed atoms, without evidence to support his idea
- 33. arranged elements in order by increasing atomic mass
- 34. mass number of a nitrogen atom containing 8 neutrons
- 35. located in the nucleus; positively charged; mass = 1 amu
- 38. atoms that have a positive or negative charge because they have unequal numbers of protons and electrons
- 41. [two words] an expression that shows the elements in a compound and the relative proportions of those elements.
- 42. [three words] depiction with negative charges distributed throughout an atom
- 43. the building blocks of matter; the smallest particles of an element that still have the element's properties
- 45. described electrons as orbiting at specific distances from the nucleus
- 46. radioactive isotope
- 47. 2 or more substances NOT chemically combined (bonded)
- 48. chemically inactive (unreactive)
- 51. a representation of an object or system that is easier to study and manipulate; the periodic table’s ability to make accurate predictions makes it a useful one of these
- 54. these occur more often in nature than do individual elements; consist of atoms of different elements chemically bonded together in fixed proportions