Chemistry Finals Study Guide

Mass = # of protons + # of neutrons

Average atomic mass = (% abundance atomic mass of isotope) + (% abundance atomic mass of isotope)

Density= mass/volume (heart)

Percent error = |Measure value-accepted value/ accepted value| * 100

Energy = planks constant *  wavelength 

Energy = Planks constant * speed of light / wavelength 

Frequency = speed of light / wavelength 

m2=m1(1/2)^(t2/t1)

m2=mass remaining

m1=original mass

t2=time

t1= half-life

Law

A statement that explains the relationship between variables. how it happens

Theory

Answer to a question that has been tested and observed (can be proven wrong)

Net ionic equation 

A chemical equation that only shows the ions directly undergoing chemical changes in a reaction. 

Spectator ion

Ions that appear on both sides of the reaction and do not take part in the reaction.

Precipitate 

A solid formed by a change in a solution from a liquid solution. 

Amplitude 

The height of the wave from the origin to the crest 

Wavelength 

The distance from one crest to the next crest 

Quantum 

A single piece of energy. The amount of energy that an object emits or absorbs is restricted. Each piece of energy is a quantum. 

Orbital 

Energy levels that electrons revolve in. (s, p, d, f)

Valence electron 

Electrons in the outermost shell of an atom, that participate in chemical bonds. 

Periodic law 

When elements are arranged by increasing atomic number, their chemical properties and physical properties show a pattern. 

Todays periodic table is arranged according to the periodic law. 

Periodic trend 

The arrangement of the periodic table reveals trends or patterns such as increasing or decreasing in the size or tendencies of melting or bonding.

Electronegativity 

The ability of an atom to attract and hold an electron. You can determine the bond type using electronegativity (find the difference in the electronegative by subtracting the two values)

Atomic radius 

The size of an atom. Can be determined by calculating half of the distance between the nucleus of an atom to the nucleus of another bonding atom. ½ distance = bond radius. Increases from top right to bottom left

Ionization energy 

The energy needed to remove an electron

Octet rule 

Atoms tend to gain or lose electrons to acquire a full set of valence electrons which is stable. Atoms obtain stability when they have 8 valence electrons. 

Hydrate 

A compound with H2O molecules in the compound. (compound that absorbs water) 

Anhydrous 

A substance containing no water

Polar bond 

One atom attracts electrons more strongly than the other 

Nonpolar bond

Electrons are equally shared 

Error 

The difference between a measured value and the true value of a substance or quantity. Accepted value- experimental value

Precision 

How close multiple measurements of the same item are to each other 

Accuracy 

How close a measurement is to the true or known value 

Derived unit 

When a unit is composed of various units. A combination of base units (from the international system of units or SI) 


Ex. area of a rectangle = length times width

Ion 

An atom that has gained or lost one or more electrons and has become electrically charged. 


Gains electrons = (-); anion 

Loses electrons = (+); cation 

Isotope 

An element that has a different number of neutrons is called an isotope 

Ex: C-12, C-14

Chain reaction 

A series of events, each caused by the previous one: 

Ex. nuclear fission 

Radioactivity 

The spontaneous emission of radiation from an atom’s nucleus. 


Ex. alpha, beta, and gamma radiation consist of particles that are emitted from the nucleus 

Half-life 

The decaying process of a radioisotope. The half-life of a radioisotope is the time it takes for one half a sample to decay 

Nuclear bombardment 

Occurs when high-speed particles collide with a nucleus. Artificially creates radioisotopes. Stable nucleus → unstable nucleus

Nuclear decay 

When an atom emits a type of radiation. The breakdown of an unstable nucleus and the emittance of a radioactive particle. 

Nuclear fission 

Occurs when a very heavy nucleus splits into two smaller nuclei 

Nuclear fusion 

Occurs when two small nuclei combine to form a larger more stable nucleus, Tremendous amounts of energy are released after

Chemical reaction 

A process in which one or more substances are converted into new substances with different physical and chemical properties 

  1. What is/are the unit of measurement for: 

    1. Mass: Grams (g),

    2. Volume: cm^3, liters (L)

    3. Length: meters (m)

    4. Atom: amu

    5. Density: g/cm^3, g/mL

JJ. Thomson: studied the flow of electric currents, discovered electrons, proposed that electrons were embedded within the atom. (w/out any organization)

"plum pudding model"

E. Rutherford: through his gold foil experiment, he proposed that protons are concentrated in a center called the nucleus. Electrons revolve in orbitals around nucleus

Bohr: the energy of each electron in an atom must be quantized. Each energy level (orbital) is given a quantum number, n. The lowest energy level (closest to nucleus) is called ground state, n=1. when an electron absorbs energy, it jumps to a higher energy level called excited state. When energy is released or emitted, the electron falls back to a lower energy level

Mendeleev: developed the early periodic table. organized elements by increasing atomic mass Arranged in a way so that the elements in the same column have similar properties

  1. State all the postulates to Dalton’s atomic theory 

    1. Atoms can neither be divided nor destroyed.

    2. All atoms of an element are identical.

    3. Atoms of different elements differ.

    4. Atoms of different elements combine in whole ratios to form compounds.

    5. Chemical reactions consist of combination, rearrangement & separation of atoms.

    Define physical and chemical changes and give 3 examples of each

    1. Physical: Changes into the same kind of matter (melting, cutting, bending)

    2. Chemical: Matter changes into a different kind of matter (chemical bonds are broken and cannot be restored), substance cannot be restored (burning, cooking, rust)

    What are the 4 types of radioactive particles? Describe the properties of each. 

    1. Alpha (α)

      1. High energy particles, represented as ​, does not have much penetrating power 

    2. Beta (β)

      1. High speed electrons, represented as , 100 times more penetrating than alpha particles 

    3. Gamma  (γ)

      1. Very energetic form of light, represented as , most penetrating and harmful

    4. Neutrons 

      1. , high penetrating (can pass through many materials), speed varies, can make objects radioactive, more penetrating than gamma radiation 

Describe the Heisenberg uncertainty principle

  1. The position of a moving object cannot simultaneously be measured and known exactly 

What does the Pauli exclusion principle state about the spins of electrons?

  1. A suborbital can only hold a maximum of 2 electrons and must have opposite spins ⇅

Early periodic table: elements organized by increasing atomic mass, arranged in a way so elements in the same column have similar properties

Todays periodic table: arranged according to periodic law, elements have a common number of valence electrons

  1. Metals (located on the left of the staircase)

    1. Good conductors of electricity 

    2. Solid at room temp (except mercury)

    3. Malleable (sheets) 

    4. Ductile (fine wires)

    5. Cations (+ charge)

  2. Nonmetals (located on the rights side of the stair case)

    1. Poor conductors of electricity 

    2. Gas, liquid, or solid at room temp

    3. Anions (- charge)

  3. Transition metals (located in the d-orbital, some in p, rectangle)

    1. Not as reactive as other metals 

    2. Typically metallic properties 

    3. Good conductors 

    4. High luster 

  4. Metalloids (located on the staircase)

    1. Semiconductors 

    2. Brittle solid at room temperature 

  5. Inner transition metals (located on f-region)

    1. Less reactive than alkaline earth metals 

    2. Soft and slippery 

    3. Radioactive 

    4. Elements after uranium are artificial

      List the main groups (families), of the periodic table and describe their unique properties 

  1. Alkali metals (group 1)

    1. high ly reactive 

    2. Reacts w/water

    3. Soft metal

    4. Good conductors

    5. Becomes plasma at high temperatures

  2. Alkali earth metals (group 2)

    1. Less reactive than group 1 

    2. Harder

    3. Denser

    4. Stronger

    5. Higher melting point

  3. Halogens (group 17)

    1. Most reactive of non metals

    2. Combien with most metals to form compounds 

    3. Halogen = salt former 

  4. Noble gases (group 18)

    1. Not very reactive

    2. Octet of electrons in outermost shell

  5. Inner transition metals - Ianthanides

    1. 4f orbitals 

    2. Less reactive than alkaline earth metals 

    3. Soft, slipper 

  6. Inner transition metals - actides 

    1. Radioactive 

    2. Elements after uranium are artificial 

  7. Hydrogen 

    1. Family all on its own 

    2. Often resembles halogens 

    3. Very reactive bcs it only has one proton and one electron

  1. Describe all the periodic trends discussed in class

    1. Atomic radii (size of an atom) increases

    2. Ionization energy (the energy needed to remove an electron) increases

    3. Electron affinity/electronegativity (the ability of an atom to attract and hold an electron) increases

Ionic Compounds 

Covalent Compounds

Metal + Metal 

Nonmetal + Metal 

Use criss cross method 

Don’t use criss cross method 

Valence electrons are transferred between elements 

Valence electrons are shared 

High melting and boiling point

Low melting and boiling point 

Conducts electricity as a liquid 

Does not conduct electricity as a liquid 

Soluble in water 

Insoluble in water 

Hard, brittle 

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