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science ch9 lesson 2
vocab+facts
Question | Answer |
---|---|
atom | the smallest particle of an element that still has the same chemical properties of the element |
nucleus | at the center of an atom and contains most of its mass |
neutrons | have no electrical charge |
protons | have a positive electrical charge |
atomic number | the number of protons in an atom element |
electrons | have a very small mass and a negative electrical charge |
periodic table | a chart that shows the elements in order of increasing atomic number |
motecule | the smallest particle of a compound that still has all the qualities of that compound |
isotopes | atoms of the same element that have different atomic massses |
Na+CI = ? | NaCI |
chemical formula | a simple way to indicate the composition of elements in a compound |
metals | conduct heat and electricity. it melts at high temperatures and can be reshaped |
nonmetals | have a dull surface and melt at lower temperatures, and tend to break when bent |
metalloids | have some properties of metals and some of nonmetals |
atomic mass | the number of protons added to the number of neutron |
which of the following has the LEAST atomic mass? A) oxygen)O) B)carbon(C) C)nitrogen(N) D)helium(He) | B: Carbon(C) |
the lead in a pencil is composed of the element_________ | carbon |
water is composed of the elements _________ and _________ | hydrogen; oxygen |
compound | a substance formed from the chemical combination of 2 or more elements that then act as a unique substance |
water is a ______ | compound |
scientists have discovered more than ____ elements | 100 |
a diamond is made of what? | carbon |
isotopes | atoms of the same element may have different numbers of neutrons |
iron | an atom that has an overoll positive or negative charge |
chemical formula | a simple way to indicate the composition of elements in a compound |