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13 Cards in this Set

  • Front
  • Back
Define atom
The basic unit of matter
Describe the size, charge, and location of three subatomic particles that make up the atom
Proton - sameness,+,nucleus
Neutron - sameness, neutral,
Electron - very light, mass o
of proton, moves around
outside of nucleus
Explain why atoms are neutral
Electrons are equal to # of protons
Define element. How are elements represented?
A pure substance containing only one type of atom
Describe an isotope.
Atoms of the same element but with different # of neutrons
Why do isotopes of the same element hav ethe same chemical properties?
Because tghey have the same # of protons and electrons
Contrast mass number and atomic number
mass number - # of protons and
atomic number - # of protons
Define compound. Give 2 examples.
A combination of 2 or more elements in definite proportions
ex. water, salt, sugar
Explain how scientists express compounds
By a formula - H2O, NaCl,
Define ionic bond
Atoms in compounds are held together by bonds, formed by the transfer of 1 or more electrons from one atom to another, NaCl
Define covalent bond
Band formed by the sharing of electrons between atoms
Describe "molecule"
The smallest unit of most chemical compounds but properties are different.
ex. - NaCl both pronouns
Describe van der Waal's forces. Give an example of a creature that uses these forces.
A slight attraction (b/t + and -) that develops b/t 2 molecular surfaces with matching shapes that are brought very close together.