- a chemical combination of two or more different elements
- compound.
- a positively charged ion
- cation
- a substance that cannot be separated into simpler substances by physical or chemical means.
- element.
- Aristotle
- influential philospher, believed Democritus' ides were incorrect and tried to disprove him.
- atomic number is equal to the number of _____ in an atom?
- electrons.
- atomic number=
- protons=electrons
- chemical changes:
- ferment, rust, explode, oxidize- changes the chemical composition.
- Democritus
- defined atoms, started the study of atoms, most of his ideas are no longer supported.
- Determined the mass-to-charge ratio of an electron
- Thomson
- electron configurations
- 1s2, 2s2...
- electrons on the outermost energy level
- valence electrons
- equation of the law of definite proportions?
- mass percentage of an element (%) = mass of element/mass of compound x 100%
- Heterogeneous mixture
- does NOT blend both substances all the way together- sand/water mixture.
- Homogenous mixture
- blends both substances together- salt/water mixture, solutions.
- John Dalton
- atomic theory, most of his ideas were correct and still believed today.
- mass number=
- electrons + protons + neutrons
- Most atoms have what kind of charge?
- they're neutral.
- negatively charged ion
- anion
- One amu (atomic mass unit) is
- 1/12 the mass of a carbon-12 atom.
- physical changes:
- crumple, crush, boil- does not change the chemical composition.
- proposed the nuclear atomic model
- Rutherford
- separates by formation of solid, pure particles from a solution.
- crystallization.
- separates solids from liquids by using a porous barrier.
- filtration.
- separates substances based on their movemtn through a special paper.
- chromatography.
- separates substances on the basis of the boiling points of the substances.
- distillation
- states that mass is neither created nor destroyed during a chemical reaction.
- law of conservation of mass
- states that regardless of the amount, a compound is always composed of the same elements in the same proportion by mass.
- Law of definite proportions.
- The atomic mass of an atom is usually not a whole number because it accounts for
- both the relative abundance and the mass of each of the atom's isotopes.
- the force that holds two atoms together.
- chemical bond
- The Law of multiple proportions
- if separate elements form 2 different compounds, the different masses of Y that combine with a fixed mass of X can be expressed as a ratio of small whole numbers.
- The number of protons in an atom is referred to as its?
- atomic number
- The number of _____ in an atom identifies it as an atom of a particular element.
- protons.
- what are the horizontal rows in the periodic table called?
- periods
- what are the vertical columns in the periodic table called?
- groups or families
- what is a neutron's charge and mass?
- 0, 1
- what is a proton's charge and mass?
- +1, 1
- what is an electron's charge and mass?
- -1, 1/1840
- where is a neutron located?
- in the nucleus.
- where is a proton located?
- in the nucleus.
- where is an electron located?
- in the space surrounding a nucleus.
