Across
- 1. this, in a chemical formula tells you how many atoms of an element are present
- 4. the mass of an electron is so ___ that it is not even considered in determining the weight of an atom
- 8. this is the small center of an atom
- 10. the electrons with the most energy that are involved in making bonds are called ____ electrons
- 11. in a single covalent bond, ___ electrons are shared between atoms
- 12. what information on a block on the PT tells you how many protons that element has in its atoms
- 13. when an atom loses an electron it becomes a ___ ion
- 15. these metals are found in group 2
- 17. this is group 18, the most unreactive elements
- 18. elements that have some properties of metals and some of nonmetals
- 19. he arranged the modern day PT
- 21. this property of metal is due to the shininess of it
- 26. a stable atom is one that has ___ valence electrons in its outer energy level (H, He, Li, and Be are exceptions)
- 27. metals are good ____ of heat and electricity
- 30. a number assigned to an element that represents the number of electrons lost (or gained, if the number is negative) by an atom of that element in the compound for it to become stable
- 32. discovered the nucleus and proton and named them both, said the atom is a lot of empty space, had the gold-foil experiment
- 35. Mendeleev created the first PT by arranging elements in order of increasing ___ ____
- 36. a covalent bond where one atom is pulling the electrons more towards it, so the sharing is unequal, it makes the molecule slightly charged
- 37. elements known as ___ are shown to the right of the metalloids on the PT
- 42. an atoms ability to attract electrons to itself when bonding to another atom
- 43. the atomic mass is the average mass of an atom of that elements protons and ____
- 44. used the word “atomos” and said there are particles so small they cannot be cut into anything smaller
- 46. matter that is composed of ONE type of atom
- 47. this means that a metal can be hammered into very thin sheets
- 49. columns on the PT are called this
- 50. at room temperature, most metals are in this state of matter
- 54. in a triple bond, this many electrons are shared between atoms
- 55. the energy needed to remove the outermost electron of an atom
- 57. horizontal rows on the PT are called this
- 58. discovered the neutron
- 59. a charged atom is called this
- 60. he was the first to arrange elements into a periodic table
Down
- 1. elements in the same group have ____ properties
- 2. molecules can attract to each other through the slightly positive and negative ends of polar covalent molecules, these are called __ __ ___ forces
- 3. this bond happens when electrons are shared between atoms
- 5. the atomic number of an element is based on the number of __ in one atom of that element
- 6. these metals are found in group 1
- 7. these elements on the PT are malleable, ductile, and can carry an electric current
- 8. ions that have bonded to form ionic compounds are electrically _____
- 9. telling me that Sodium’s electrons are arranged as 2,8,1 is telling me Sodium’s electron _____
- 14. the ___ metals are groups 3-12 on the PT
- 16. these metals are found in groups 3-12
- 20. a covalent bond where atoms are sharing electrons equally
- 22. in a neutral atom, the number of protons equals the number of ____
- 23. came up with the “plum-pudding” model of the atom
- 24. we use this model to show how all the electrons in an atom are arranged in energy levels, he said like the orbits of planets around the sun
- 25. the mass of an atom is the sum of all it’s isotopes on earth and the units used to express it are ___ ___ ___
- 28. hydrogen is usually shown in Group one,on the side with metals, but it is actually a ____
- 29. in a double covalent bond, this many electrons are shared between atoms
- 31. this method is writing the element’s symbol then showing dots to represent the number of valence electrons
- 33. came up with the electron cloud model of the atom
- 34. a metal is called this because it can be drawn out into thin wire
- 38. each element on the PT is given a unique ___ to represent that element
- 39. ions that are made of more than one atom are called this, like CO3-2
- 40. F, Cl, and Br belong to Group 17, also called the ____ group
- 41. this type of bond forms between positive and negative ions
- 43. elements in the same period have the same ____ of electron energy levels
- 45. if an element has 8 valence electrons naturally, or if it bonds with another atom to acquire 8, then it is called ___
- 48. came up with the Atomic theory and 4 statements about atoms
- 51. when naming compounds and molecules of atoms that have bonded together, you change the ending of the last element with these 3 letters
- 52. electrons carry this charge
- 53. protons carry this charge
- 56. Atoms of the same element that have different number of neutrons
- 57. when naming covalently bonded atoms, you name the molecule using a ____ to show how many atoms of that element there are