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Science Explosion 08
BJU 6th Science - Chapter 7
| Question | Answer |
|---|---|
| Chemistry | study of matter |
| Atom | smallest piece of an element |
| Element | substance containing only one kind of atom |
| Nucleus | center section of an atom |
| Proton | positive charge |
| Neutron | no charge |
| Atomic mass | sum of protons and neutrons |
| Electron | negatively charged |
| Shell | average distance of the electrons from the nucleus |
| Atomic number | number of protons in an atom’s nucleus |
| Atomic theory | scientists ideas about atoms |
| Particle accelerator | atom smasher |
| Chemical symbol | abbreviations for elements |
| Periodic table of the elements | classification system |
| Period | horizontal rows of periodic table |
| Group | vertical columns of table |
| Family | color coded groups on periodic table |
| Molecule | atoms joined together |
| Chemical reaction | a chemical change |
| Compound | molecules produced by a reaction |
| Chemical formula | symbols and numbers used to abbreviate a compound |
| Closed | outer most shell of an atom is full |
| Covalent bond | atoms sharing pairs of electrons |
| Ion | atom that has gained or lost an electron |
| Positive ion | an atom with fewer electrons than usual |
| Negative ion | an atom with more electrons than usual |
| Ionic bond | positive and negative ions attracted to each other |
| Endothermic reaction | reaction that uses heat energy |
| Exothermic reaction | reaction the produces heat |
| Acid | form hydrogen ions when dissolved in water |
| Base | form hydroxide ions when dissolved in water |
| Alkali | bases that dissolve in water |
| pH scale | “power of hydrogen”; numbered from 0-14 |
| indicator | changes color when exposed to acid or base |
| neutral | pH of 7.0 |
| neutralize | when an acid and base combine and “cancel “each other out |
| salt | ionic compound formed during a reaction with a base and an acid |