chem exam 1 2
Terms
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- law of conservation of mass
- mass is neither created not destroyed
- law of definite proportion
- a given comppund always contains exactly the same proportion of elements by mass
- law of multiple proportions
- states that when two elements form a series of compounds, the ratios of the masses of the second element that combine with the one gram of the first element can always be reduced to small whole numbers
- atomic masses/weights
- the average mass of the atoms in a naturally occurring element
- mass number
- the total number of protons and neutrons
- Avogadro's hypothesis
- at the same temperature and pressure, equal volumes of different gases contain the same number of particles
- cathode-ray tube
- emanate the negative electrode
- electron
- negatively charged particles
- radioactivity
- emission of radiation by the uranium
- nuclear atom
- an atom with a dense center of positive charge
- nucleus
- the small dense center of positive charge in n atom
- proton
- have a positive charge particle equal to the magnitude to the electron's negative charge
- neutron
- have virtually the same mass as a proton but no charge
- isotopes
- atoms with the same number of protons but different numbers of neutrons
- atomic number
- the number of protons in the nucleus of an atom
- chemical bond
- the forces that hold atoms together in compounds
- covalent bond
- bonds that share electrons
- molecule
- collection of atoms
- chemical formula
- the symbols for the elements are used to indicate the types of atoms present and subscripts are used to indicate the relative number of atoms
- structural formula
- individual bonds are shown using lines
- space-filling model
- shows the relative sizes of the atoms as well as their relative orientation in the molecule
- ball and stick model
- represent molecules
- ion
- an atom or group of atoms that has a net positive or negative charge
- cation
- a positive ion
- anion
- a negative ion
- ionic bond
- force of attraction between oppositely charged ions
- ionic solid (salt)
- a solid consisting of oppositley charged ions
- polyatomic ion
- an ion containing a number of atoms
- periodic table
- shows all the known elements and gives a good deal of information about each
- metal
- tend to lose electrons to form positive ions