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What is the basic unit of matter?
atom
What is the center of the atom called?
nucleus
What subatomic particles are found in the nucleus of an atom?
protons and neutrons
What subatomic particles have a negative charge?
electrons
What subatomic particles have a positive charge?
protons
What is a chemical element?
pure substance that consists entirely of one type of atom
Identify the element by it's symbol: C
carbon
Identify the element by it's symbol: H
hydrogen
Identify the element by it's symbol: Na
sodium
What elements make most of the mass of living things?
carbon, hydrogen, phosphorous, oxygen, nitrogen, calcium
What are isotopes?
atoms of the same element with different numbers of neutrons
Do the chemical properties of isotopes differ?
no
What makes an isotope radioactive?
when its nucleus is unstable and breaks down at a constant rate over time
What is a compound?
a substance formed by the chemical combination of two or more elements in definite proportions
What is an example of a compound?
Hint: we drink it to survive
Water
How are atoms in compounds held together?
chemical bonds
Electrons in an atom's outer shell that are available to form bonds are called...
valence electrons
What are the main types of chemical bonds?
Ionic bonds and covalent bonds
How are ionic bonds formed?
by the transfer of electrons
How are covalent bonds formed?
by sharing electrons
What is an ion?
a positively or negatively charged atom
What is a molecule?
two or more atoms held together by chemical bonds
What are hydrogen bonds?
a weak bond that forms between a hydrogen atom of one molecule and an oxygen or nitrogen atom of a neighboring molecule
What are Van der Waals forces?
when molecules are close together, a slight attraction can develop, and if two molecules have shapes that match so they can fit against each other with little space between them, the forces may be strong enough to hold the molecules together
Note 
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