Question | Answer |
What are the building blocks of matter? | Elements |
What is the difference between compounds and mixtures? | A compound is pure substance made of two or more elements chemically combined in a specific ratio. IE:water A mixture is made up of two or more substances (elements or compounds) that are in the same vicinity but not chemically combined. IE: air |
Who originally thought up the atomic theory? | The ancient Greeks. |
What was John Dalton's original atomic theory? | *all atoms of the same element are the same *atoms of 1 element can't be changed into another *atoms can't be created or destroyed, only rearranged *smooth hard balls that can't be broken down |
List each scientist and their contribution to the atomic theory. | *John Dalton~orig. theory *JJ Thomson~- chrged part. in a + base *Ernest Rutherford~electrons orbit around a small + nucleus (gold foil exp) *Niels Bohr~electrons move in specific orbits *orbit in a cloudlike reigon depending on its energy level *neutrons |
What are valence electrons? | The electrons in an atom that have the highest energy level and are held most loosely. Number ranges from 1-8. |
What is the electron dot diagram? | A diagram that has the symbol of an element surrounded by dots. Each dot resembles one valence electron. |
What makes an atom stable? | A stable atom has 8 valence electrons, by itself, ionicly bonded, or covalently bonded |
What can the periodic table tell you about an element? | *atomic number (# of protons and neutrons) *Symbol *Atomic mass (protons + neutrons) *valence electrons *solid/liquid/gas *metal/nonmetal/metalloid |
What are the sections of the periodic table? | Periods go across, groups or families go down. |
Which atoms want to get electrons? Which ones want to give them away? | Atoms with 5+ valence electrons want to gain them (families 13-17) Atoms with 4- electrons want to lose them (families 1-12). |
What are the parts of an atom? | Electrons (-) and the nucleus, which is made up of protons (+) and neutrons ( ) |
What is an ion and how is it formed? | An ion is an atom with an electric charge. When an atom loses an electron, it becomes positive. When it gains an electron, it becomes negative. |
What is an ionic bond? | The attraction between two oppositely charged ions. IE:Sodium Chloride (Na+Cl-) |
What is an ionic compound? What are its properties? | An ionic compound is a compound that consists of both positive and negative ions. They are very hard and fragile, have high melting points, and conduct electricity when liquid. |
What is a covalent bond? | The bond formed when two atoms share electrons. IE:Water (H2O) |
What is a molecular compound? What are its properties? | A molecular compound is a compond composed of molecules, has covalent bonds. They have low melting points and bad conductivity. |
What is the difference between ionic and covalent bonds? | Ionic bonds give and take electrons, covalent bonds share them. |
What is the difference between ionic and molecular compounds? | Ionic compounds are made of ions, ionicly combined. Molecular compounds are made of molecules, covalently combined. Ionic compounds have higher boiling points and conduct electricity better. |
What is the difference between polar and nonpolar bonds? | Nonpolar bonds have an equal pull in both directions, balancing it out. -+- (<-->) Polar bonds have a stronger pull at one end, making one part slightly negative and the other slightly positive. =+ (-->) |