Across
- 4. _______________ organized the modern periodic table of the elements in order of increasing atomic number.
- 7. An ___________ is a region of the atom where there is a high probability of finding an electron.
- 9. Group 17 elements, also known as __________________, are very reaction.
- 10. A __________ is a vertical column of the periodic table.
- 15. A charged an is called an _______________.
- 16. A __________ is a horizontal row of the periodic table.
- 18. _____________ discovered the neutron.
- 20. _______________ determined atoms of each element are alike.
- 21. The six elements on the zig-zag of the periodic table which can have properties of metals under certain conditions are called _________________.
- 25. The ____________ is the positively-charged central region of an atom.
- 28. A negatively-charged atom is called an ______________.
- 29. ____________ law states that properties of elements repeat at regular intervals.
- 31. The ____________ number equals the number of protons in an atom's nucleus.
- 32. The ____________ is one of the subatomic particles in an atom's nucleus.
- 33. The second energy level can hold ________ electrons.
- 35. Each element has a ___________ number of protons.
- 36. ________________ discovered the electron.
- 37. In order for an atom to become positively-charged, it must __________ electrons.
- 40. Elements can be classified as _____________, nonmetals, or semiconductors.
- 42. Isotopes are atoms that have the same atomic number, but a ______________ number of protons.
Down
- 1. The gases in Group 18 are known as ___________ gases.
- 2. The first energy level can hold ________ electrons.
- 3. This element is the most abundant element in the universe.
- 5. A positively-charged atom is called a _____________.
- 6. ________________ electrons are the electrons in atom's outermost energy level.
- 8. The number of valence electrons an element has determines many of the element's ____________ properties.
- 10. In order for an atom to become negatively-charged, it must _________ electrons.
- 11. Elements in a group of the periodic table share similar ______________.
- 12. The ________________ is a subatomic particle outside an atom's nucleus.
- 13. The metals found in the middle of the periodic table are called _____________ metals.
- 14. Group 1 metals, also known as ____________ metals, are very reactive.
- 17. An atom that has the number number of protons but a different number of neutrons as another atom is that atom's _____________.
- 19. _____________ stated the the location of an electron could not be determined.
- 22. _______________ determined that all matter is made up of indivisible pieces called atoms.
- 23. __________________ determined that most of an atom's mass was in its nucleus.
- 24. A __________ represents an element using one upper-case or one upper-case and one lower-case letter
- 26. An element's ____________ on the periodic table is related to its number of valence electrons.
- 27. ________________ organized a periodic table of the elements in order of increasing atomic mass.
- 30. Noble gases are ____________ because they do not react with other elements under normal conditions.
- 34. ________________ determined electrons orbit the nucleus at fixed energy levels.
- 38. The __________ number equals the sum of the number of protons and neutrons in an atom's nucleus.
- 39. The _____________ is one of the subatomic particles in an atom's nucleus.
- 41. An atom is an ion when the number of protons and electrons is an atom are not ___________.
- 43. The elements in a __________________ have the same number of valence electrons.