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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 |