Review for Test
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- the Rutherford Model
- 1911, Ernest Rutherford, thought atom was mostly empty space, electrons randomly orbit a small, positively charged nucleus
- crystalline solid
- a solid that is made up of crystals
- what 3 parts make up an atom?
- protons, neutrons, electrons
- what is the temperature in which water freezes?
- 0 degrees celsius
- Boyle's law
- when the pressure of a gas increases at constant temperature, the volume decreases and vise versa. graph makes a curve
- heterogeneous mixture
- a mixture where you can see the different parts. example: soil
- chemical change
- a change in matter that produces one or more new substances
- what happens when elements are combined?
- their properties change completely from the properties of the compound uncombined
- the Bohr Model
- 1913, Niels Bohr, said that electrons formed specific layers instead or random ones, said atoms atoms absorb and give off energy when the electrons move from one shell to another
- chemical formula
- shows the elements in the compound and the ratio of atoms
- the Dalton Model
- 1808, John Dalton, elements are made of atoms that are all alike, thought different elements had different mass, tiny solid balls
- mixture
- made of two or more substances (elements, compounds, or both) that are together in the same place but not combined
- liquid
- has a definite volume but not a definite shape. the particles are free to move
- gas
- a state of matter with no definite shape or volume
- electrons
- move rapidly around the nucleus and have a negative charge (-)
- temperature
- the measure of the average energy in the particles of matter
- viscosity
- a liquids resistance to flowing
- boiling
- takes place below the surface as well as the surface
- changes of state
- solid, liquid, gas
- volume
- the amount of space that matter occupies. common measurements: liter, milliliter, cubic centimeter
- solid
- has a definite shape and volume. the particles in a solid are closely packed
- matter
- anything that has mass and takes up space
- density formula
- density = mass/volume
- what happens when the temperature of a gas at constant volume increases?
- the pressure increases and vise versa
- atomic number
- the number of protons in an element's nucleus
- physical property
- a characteristic of a pure substance that can be observed without changing it into another substance
- what is the temperate in which water boils?
- 100 degrees celsius
- physical change
- any change that alters the form of appearance of matter but does not change the substance into a different one
- period
- horizontal row. properties change from left to right in a pattern in a perioud
- what kinds of properties are chemical?
- creating new substances with new properties, flammability, ability to react (such as rusting, tarnishing)
- kinetic theory
- explains properties of gases pressure, temperature, and volume by considering the movement of particles
- gas
- does not have a definite shape or volume. particles move in the air
- neutrons
- have no charge (±) neutral
- compound
- a pure substance made of two or more elements chemically combined in a set ratio
- what happens to the elements and compounds in a mixture?
- each substance in a mixture keeps its individual properties; the properties are not combined in a set ratio
- homogeneous mixture
- a mixture that is so evenly mixed that you cannot see the different parts. example: solution
- actinides
- no uses, very unstable, can last for fractions of a second
- mass number
- the sum of protons and neutrons in the nucleus of an atom (such as carbon-12, 6 neutrons + 6 electrons)
- isotopes
- atoms with the same number of protons and a different number of neutrons
- what kinds of properties are physical?
- hardness, texture, color, state of matter, ability to conduct heat and electricity, flexibility; can be used to classify matter
- substance
- a single kind of matter that is pure (has a specific makeup) and a specific set of properties
- chemistry
- the study of the properties of matter and how matter changes
- changes of shape of form
- bending, crushing, breaking, chopping...
- amorphous solid
- a solid that is made up of particles in an irregular pattern
- group
- column a.k.a family, families have the similar characteristics
- what is helpful to know when working with gases?
- volume, temperature, pressure
- evaporation
- takes place at the surface of a liquid
- Charles's law
- when the temperature of a gas increases at constant pressure volume increases and vise versa. graph makes a straight line
- what two kinds of properties does all matter have?
- physical properties and chemical properties
- vaporization
- the change from a liquid to a gas
- chemical property
- a characteristic of a pure substance that describes its ability to change into different substance
- alkali metals (#1)
- react by losing one electron. rarely found uncombined in nature. react with water. uses: some in batteries and medicines, essential to life
- valence electrons
- the number of electrons in the outermost shell of an atom. determines how well it reacts with other substances. the fewer valence electrons the less likely it is to react and the less stable it is
- endothermic change
- a change in which energy is taken in. example: melting ice
- exothermic change
- the release of energy from a substance. example: combustion
- transition metals
- uses: jewellery, coins, electric wires, paint
- why is mass better than weight when measuring substances?
- mass is better because it is always constant and weight depends on the amount of gravity pushing down
- characteristic property
- a characteristic of a pure substance that describes its ability to change into a different substance
- thermal energy
- the total energy of all the particles in an object
- nucleus
- the very small center core of an atom
- lanthanides
- uses: alloys (a mixture of two or more metals), speakers
- protons
- have a positive charge (+)
- pressure
- the outward push of a gas on the walls of its container (pressure = force/area)
- alkaline earth metals (#2)
- good conductors, react by losing two electrons, not as reactive as alkali metals, rarely found uncombined in nature. uses: ladders, airplane parts, car wheels
- weight
- the measure of the force of gravity on you
- energy
- the ability to do work; every chemical and physical change includes a change in energy
- metals in mixed groups
- uses: car batteries, weights
- mass
- the measurement of the amount of matter in an object